Search

Your search keyword '"Annie Brûlet"' showing total 118 results
Start Over Author "Annie Brûlet"
Sorry, I don't understand your search. ×
118 results on '"Annie Brûlet"'

1. In situ monitoring of block copolymer self-assembly via solvent exchange through controlled dialysis with light and neutron scattering detection

Author

Martin Fauquignon, Lionel Porcar, Annie Brûlet, Jean-Francois Le Meins, Olivier Sandre, Jean-Paul Chapel, Marc Schmutz, and Christophe Schatz

Abstract

Solution self-assembly of amphiphilic block copolymers (BCs) is typically performed by solvent to water exchange. However, BC assemblies are often trapped in metastable states depending on the mixing conditions, such as the magni-tude and rate of water addition. BC self-assembly can be performed under near thermodynamic control by dialysis which accounts for a slow and gradual water addition. In this communication we report the use of a specifically de-signed dialysis cell to continuously monitor by dynamic light scattering and small-angle neutron scattering the mor-phological changes of PDMS-b-PEG BCs during THF to water exchange. The complete phase diagrams of near-equilibrium structures can then be established. Spherical micelles first form before evolving to rod-like micelles and vesicles, decreasing the total developed interfacial area of self-assembled structures in response to increasing interfacial energy as the water content increases. The dialysis kinetics can be tailored to the time scale of BC self-assembly by modifying the membrane pore size, which is of interest to study the interplay between thermodynamics and kinetics in self-assembly pathways.

Published
2023
Full Text
View/download PDF

2. Polymersomes with a smectic liquid crystal structure and AIE fluorescence

Author

Nian Zhang, Yujiao Fan, Hui Chen, Sylvain Trépout, Annie Brûlet, and Min-Hui Li

Subjects
Polymers and Plastics, Organic Chemistry, Bioengineering, Biochemistry
Abstract

Fluorescent smectic polymersomes with aggregation-induced emission are prepared from an amphiphilic block copolymer containing a liquid crystal hydrophobic block and a tetraphenylethene-bearing unit between hydrophilic and hydrophobic blocks.

Published
2022
Full Text
View/download PDF

3. In situ monitoring of block copolymer self-assembly through con-trolled dialysis with light and neutron scattering detection

Author

Martin Fauquignon, Lionel Porcar, Annie Brûlet, Jean-Francois Le Meins, Olivier Sandre, Jean-Paul Chapel, Marc Schmutz, Christophe Schatz, Laboratoire de Chimie des Polymères Organiques (LCPO), Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Team 3 LCPO : Polymer Self-Assembly & Life Sciences, Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche Paul Pascal (CRPP), Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Charles Sadron (ICS), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), and Chapel, Jean-Paul

Subjects
block copolymers, [CHIM.POLY] Chemical Sciences/Polymers, [CHIM.POLY]Chemical Sciences/Polymers, self-assemby, dialysis, Light and Neutron Scattering, [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], [PHYS.COND.CM-SCM] Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]
Abstract

Solution self-assembly of amphiphilic block copolymers (BCs) is typically performed by solvent to water exchange. However, BC assemblies are often trapped in metastable states depending on the mixing conditions, such as the magni-tude and rate of water addition. BC self-assembly can be performed under near thermodynamic control by dialysis which accounts for a slow and gradual water addition. In this communication we report the use of a dialysis cell specif-ically designed to continuously monitor by dynamic light scattering and small-angle neutron scattering the morpho-logical changes of PDMS-b-PEG BCs during THF to water exchange. The complete phase diagrams of equilibrium structures can then be established. Spherical micelles first form before evolving to rod-like micelles and vesicles, de-creasing the total interfacial area of aggregates in response to increasing interfacial energy. The dialysis kinetics can be adapted to the time scale of self-assembly by modifying the membrane pore size. The approach described herein should be relevant in polymer self-assembly and in supramolecular chemistry in general to better understand the interplay between thermodynamics and kinetics in aggregate formation.

Published
2022
Full Text
View/download PDF

4. Fatty-acid based comb copolyesters as Viscosity Index Improvers in Lubricants

Author

Hélène Méheust, Jean-François Le Meins, Annie Brûlet, Olivier Sandre, Etienne Grau, Henri Cramail, Team 2 LCPO : Biopolymers & Bio-sourced Polymers, Laboratoire de Chimie des Polymères Organiques (LCPO), Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Team 3 LCPO : Polymer Self-Assembly & Life Sciences, Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), LLB - Matière molle et biophysique (MMB), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Fédération de recherche INCREASE (INCREASE), Institut des Sciences Moléculaires (ISM), Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1 (UB)-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Montesquieu - Bordeaux 4-Université Sciences et Technologies - Bordeaux 1 (UB)-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie des Milieux et Matériaux de Poitiers (IC2MP), Université de Poitiers-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Poitiers-Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de Chimie des Polymères Organiques (LCPO), Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Centre National de la Recherche Scientifique (CNRS)-Laboratoire de Génie Chimique (LGC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Unité de recherche sur les Biopolymères, Interactions Assemblages (BIA), Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre de recherche sur l'intégration économique et financière (CRIEF), Université de Poitiers-Université de Poitiers, and ANR-10-EQPX-0016,XYLOFOREST,Plateforme d'Innovation ' Forêt-Bois-Fibre-Biomasse du Futur '(2010)

Subjects
bio-based copolyesters, Viscosity Index, [CHIM.POLY]Chemical Sciences/Polymers, Polymers and Plastics, conformational behavior, viscosity modifiers, thickeners, SANS, Organic Chemistry, lubricant, Materials Chemistry, General Physics and Astronomy, polyricinoleate
Abstract

International audience; Methyl ricinoleate was functionalized using thiol-ene click chemistry in order to synthesize bio-based comb (co)poly(9-alkyl 12-hydroxystearate)s. The latter were then evaluated as Viscosity Index Improvers in a mineral based lubricant. While most of the poly(9-alkyl 12-hydroxystearate)s investigated behave as thickeners, copolyesters containing 15 to 25 wt. % of methyl 9-phenyl ethyl 12-hydroxystearate exhibit a Viscosity Index improver effect, interpreted to a limited solubility of these copolyesters. The effect of these polyesters on the oil viscosity-temperature (V-T) behavior was investigated in the dilute regime of n-dodecane used as a model solvent. An aggregation-disaggregation behavior was assumed to explain the V-T behavior observed with these (co)polyesters.

Published
2022
Full Text
View/download PDF

5. Fluorescent polymer cubosomes and hexosomes with aggregation-induced emission

Author

Annie Brûlet, Nian Zhang, Bergam Ptissam, Yujiao Fan, Ben Zhong Tang, Min-Hui Li, Hui Chen, Sylvain Trépout, Institut de Recherche de Chimie Paris (IRCP), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Ministère de la Culture (MC)

Subjects
chemistry.chemical_classification, Materials science, Small-angle X-ray scattering, 02 engineering and technology, General Chemistry, Polymer, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Fluorescence, 0104 chemical sciences, 3. Good health, Chemistry, Colloid, chemistry, Chemical engineering, Amphiphile, Copolymer, [CHIM]Chemical Sciences, Fluorescent polymer, 0210 nano-technology, Pendant group
Abstract

Fluorescent polymer cubosomes and hexosomes with aggregation-induced emission (AIE) were prepared from amphiphilic block copolymers PEG-b-PTPEMA where the hydrophobic block PTPEMA was a polymethacrylate with tetraphenylethene (TPE) as the AIE side group. Four highly asymmetric block copolymers with hydrophilic block weight ratio fPEG ≤ 20% were synthesized. Cubosomes and hexosomes with strong fluorescence emission were obtained by nanoprecipitation of polymers with fPEG < 9% in dioxane/water and THF/water systems. Their ordered internal structures were studied by electron microscopy (cryo-EM, SEM and TEM) and the X-ray scattering technique (SAXS). To elucidate the formation mechanisms of these inverted colloids, other parameters influencing the morphologies, like the water content during self-assembly and the organic solvent composition, were also investigated. This study not only inspires people to design novel building blocks for the preparation of functional cubosomes and hexosomes, but also presents the first AIE fluorescent polymer cubosome and hexosome with potential applications in bio-related fields., Fluorescent Im3̄m cubosome and P6mm hexosome with aggregation-induced emission (AIE) were reported, which were formed by amphiphilic block copolymers PEG-b-PTPEMA. The length of hydrophobic block PTPEMA was adjusted to control morphology formation.

Published
2021
Full Text
View/download PDF

6. Effect of the microstructure of n-butyl acrylate/N-isopropylacrylamide copolymers on their thermo-responsiveness, self-organization and gel properties in water

Author

Stéphane Gineste, Fang Yin, Mariana Beija, Juliette S. Behra, Nancy Lauth-de Viguerie, Bruno Payré, Annie Brûlet, Juliette Fitremann, Mathias Destarac, Jean-Daniel Marty, Interactions moléculaires et réactivité chimique et photochimique (IMRCP), Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Fédération de Recherche Fluides, Energie, Réacteurs, Matériaux et Transferts (FERMAT), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), IDeAS - Interfaces Dynamiques et Assemblages Stimulables (IDeAS), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT), P3R - Polymères de Précision par Procédés Radicalaires (P3R), LLB - Matière molle et biophysique (MMB), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Centre de Microscopie Électronique Appliquée à la Biologie (CMEAB), Toulouse Réseau Imagerie-Genotoul ( TRI-Genotoul), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Hôpital de Rangueil, CHU Toulouse [Toulouse]-CHU Toulouse [Toulouse]-Toulouse Réseau Imagerie-Genotoul ( TRI-Genotoul), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)

Subjects
Cloud point, Acrylate, Molar mass, Materials science, 02 engineering and technology, Neutron scattering, 010402 general chemistry, 021001 nanoscience & nanotechnology, Microstructure, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Biomaterials, chemistry.chemical_compound, Colloid and Surface Chemistry, Differential scanning calorimetry, chemistry, Chemical engineering, 13. Climate action, Copolymer, [CHIM]Chemical Sciences, Thermoresponsive polymers in chromatography, 0210 nano-technology
Abstract

International audience; AbstractHypothesisPolymer composition, microstructure, molar mass, architecture… critically affect the properties of thermoresponsive polymers in aqueous media.ExperimentsThe behaviour of n-isopropylacrylamide and n-butyl acrylate-based copolymers of variable composition and structure (statistical, diblock or triblock) was studied in solution at different temperatures and concentrations with turbidimetry measurements, differential scanning calorimetry, electronic microscopy, rheology and scattering experiments.FindingsThis study illustrates how it is possible through chemical engineering of the microstructure of amphiphilic thermoresponsive polymers to modulate significantly the self-assembly, morphological and mechanical properties of these materials in aqueous media. Statistical structures induced a strong decrease of cloud point temperature compared to block structures with similar composition. Moreover, block structures lead below the transition temperature to the formation of colloidal structures. Above the transition temperature, the formation of colloidal aggregates is observed at low concentrations, and at higher concentrations the formation of gels. Neutron scattering and light scattering measurements show that for a given composition diblock structures lead to smaller colloids and mesoglobules than their triblock counterparts. Moreover, diblock structures, compared to triblock analogs, allow the formation of gels that do not demix with time (no synaeresis) but that are softer than triblock gels.Graphical abstractThe microstructural engineering of amphiphilic thermoresponsive copolymers of n-butyl acrylate and N-isopropylacrylamide allows significant modulations of the self-assembly, morphological and mechanical properties of these materials in aqueous media.

Published
2020
Full Text
View/download PDF

7. Monitoring food structure in plant protein gels during digestion: Rheometry and Small Angle Neutron Scattering studies

Author

Maja Napieraj, Annie Brûlet, Evelyne Lutton, Urielle Randrianarisoa, Adeline Boire, François Boué, LLB - Matière molle et biophysique (MMB), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Paris-Saclay Food and Bioproduct Engineering (SayFood), AgroParisTech-Université Paris-Saclay-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Mathématiques et Informatique Appliquées (MIA Paris-Saclay), Unité de recherche sur les Biopolymères, Interactions Assemblages (BIA), and Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)

Subjects
Protein, Bioengineering, Gastrointestinal digestion, Rheological properties, Small Angle Neutron Scattering, Applied Microbiology and Biotechnology, [SDV.AEN]Life Sciences [q-bio]/Food and Nutrition, Canola proteins, Protein gels, Food Science
Abstract

International audience; We studied rheology and nanostructures (by Small Angle Neutron Scattering) of heat-set canola seed protein gels, containing cruciferin and napin, prepared at pH 8 and pH 11. We focused on gastric and intestinal digestion of 10 mm pieces, mimicking human gastro-intestinal tract. Stronger gels, prepared at pH 11 (above the isoelectric points (IEP), of both proteins), retained local folded and compact conformations, close to native ones. Preparation at pH 8 (below napin's IEP but above cruciferin's one), could destabilize conformations due to charge differences of the proteins. For preparation pH 8, proteins were almost unfolded, and the gel softer. In gastric digestion, modulus decreased for pH 8 gels, but surprisingly, increased for pH 11. We propose a competition between unfolding, increasing local interactions (hence the modulus), and enzymatic scission. Scission could be less efficient for pH 11 gels, with less unfolded proteins and higher crosslink density, hindering enzymatic diffusion. Additional interactions could result from crossing one or two IEPs, towards gastric pH 2. For intestinal digestion, the two gels behave similar (proteins re-compaction and modulus decrease). Beyond loss of submicronic connectivity, external erosion of the gel for largest times is observed, but less on SANS, which involves the center of the piece.

Published
2022
Full Text
View/download PDF

8. Structure of proteins under pressure: Covalent binding effects of biliverdin on β-lactoglobulin

Author

Simeon Minić, Burkhard Annighöfer, Arnaud Hélary, Laïla Sago, David Cornu, Annie Brûlet, Sophie Combet, Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), LLB - Matière molle et biophysique (MMB), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), LLB - Infrastructures et développement (INFRA), and Institut de Biologie Intégrative de la Cellule (I2BC)

Subjects
[SDV.BBM.BP]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biophysics, [SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM], Biliverdine, Biophysics, Animals, [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Cattle, Cysteine, Lactoglobulins, Article, Protein Unfolding
Abstract

International audience; High pressure (HP) is a particularly powerful tool to study protein folding/unfolding, revealing subtle structural rearrangements. Bovine β-lactoglobulin (BLG), a protein of interest in food science, exhibits a strong propensity to bind various bioactive molecules. We probed the effects of the binding of biliverdin (BV), a tetrapyrrole linear chromophore, on the stability of BLG under pressure, by combining in situ HP-small-angle neutron scattering (SANS) and HP-UV absorption spectroscopy. Although BV induces a slight destabilization of BLG during HP-induced unfolding, a ligand excess strongly prevents BLG oligomerization. Moreover, at SANS resolution, an excess of BV induces the complete recovery of the protein “native” 3D structure after HP removal, despite the presence of the BV covalently bound adduct. Mass spectrometry highlights the crucial role of cysteine residues in the competitive and protective effects of BV during pressure denaturation of BLG through SH/S-S exchange.

Published
2022
Full Text
View/download PDF

9. Large Hybrid Polymer/Lipid Unilamellar Vesicle (LHUV) at the nanoscale: An insight into the lipid distribution in the membrane and permeability control

Author

Annie Brûlet, Martin Fauquignon, Elise Courtecuisse, Jean-François Le Meins, Angela Mutschler, Marc Schmutz, Romane Josselin, Laboratoire de Chimie des Polymères Organiques (LCPO), Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC), Team 3 LCPO : Polymer Self-Assembly & Life Sciences, Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Groupe Diffusion petits angles (GDPA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, LLB - Matière molle et biophysique (MMB), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Institut Charles Sadron (ICS), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA), Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), and Admin, Oskar

Subjects
Polymersomes, [CHIM.POLY] Chemical Sciences/Polymers, Materials science, Membrane permeability, Polymers, Lipid Bilayers, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Nanoreactor, Permeability, Polyethylene Glycols, Membrane Permeability, Biomaterials, chemistry.chemical_compound, Colloid and Surface Chemistry, Small Angle Neutron Scattering (SANS), POPC, Unilamellar Liposomes, Liposome, Molar mass, Vesicle, Membrane structure, technology, industry, and agriculture, Cryo Transmission Electron Microscopy (Cryo-TEM), 021001 nanoscience & nanotechnology, [PHYS.COND.CM-SCM] Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Molecular Weight, Membrane, [CHIM.POLY]Chemical Sciences/Polymers, Chemical engineering, chemistry, Hybrid Polymer/Lipid Vesicle, Polymersome, Liposomes, lipids (amino acids, peptides, and proteins), 0210 nano-technology, [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]
Abstract

Membrane structuration of Large Hybrid Unilamellar Polymer/Lipid Vesicle (LHUV) is an important parameter on the optimization of their properties and thus their valuation in various fields. However, this kind of information is hardly accessible. In this work, we will focus on the development of LHUV obtained from the self-assembly of diblock poly(dimethylsiloxane)-b-poly(ethylene oxide) (PDMS-b-PEO) of different molar masses combined with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) at 15% and 25% w/w content. The hybrid character of the resulting vesicles as well as their membrane structure are characterized by the mean of different techniques such as small-angle neutron scattering (SANS) and cryo-transmission electron microscopy (cryo-TEM). We show that hybrid vesicles with homogeneous membrane structure are obtained whatever the molar mass of the block copolymer (from 2500 to 4000 g/mol), with of a small number of tubular structures observed with the higher molar mass. We also demonstrate that the permeability of the LHUV, evaluated through controlled release experiments of fluorescein loaded in LHUV, is essentially controlled by the lipid/polymer composition.

Published
2021
Full Text
View/download PDF

10. Direct Access to Polysaccharide-Based Vesicles with a Tunable Membrane Thickness in a Large Concentration Window via Polymerization-Induced Self-Assembly

Author

Djallal Ikkene, Ana Andreea Arteni, Annie Brûlet, Khalid Ferji, Grégory Francius, Jean-Luc Six, and Malika Ouldali

Subjects
Materials science, Polymers and Plastics, Polymers, Vesicle, Bioengineering, Chain transfer, 02 engineering and technology, Degree of polymerization, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Micelle, 0104 chemical sciences, Polymerization, Biomaterials, Dynamic light scattering, Chemical engineering, Polysaccharides, Polymersome, Materials Chemistry, Copolymer, 0210 nano-technology, Hydrophobic and Hydrophilic Interactions, Micelles
Abstract

Polymersomes are multicompartmental vesicular nano-objects obtained by self-assembly of amphiphilic copolymers. When prepared in the aqueous phase, they are composed of a hydrophobic bilayer enclosing water. Although such fascinating polymeric nano-objects have been widely reported with synthetic block copolymers, their formation from polysaccharide-based copolymers remains a significant challenge. In the present study, the powerful platform technology known as polymerization-induced self-assembly was used to prepare in situ pure vesicles from a polysaccharide-grafted copolymer: dextran-g-poly(2-hydroxypropyl methacrylate) (Dex-g-PHPMA). The growth of the PHPMA grafts was performed with a dextran-based macromolecular chain transfer agent in water at 20 °C using photomediated reversible addition fragmentation chain transfer polymerization at 405 nm. Transmission electron microscopy, cryogenic electron microscopy, small-angle X-ray scattering, atomic force microscopy, and dynamic light scattering revealed that amphiphilic Dex-g-PHPMAX = 100-300 (X is the targeted average degree of polymerization, Xn, of each graft at full conversion) exhibit remarkable self-assembly behavior. On the one hand, vesicles were obtained over a wide range of solid concentrations (from 2.5% to 13.5% w/w), which can facilitate posterior targeting of such rare morphology. On the other hand, the extension of Xn induces an increase in the vesicle membrane thickness, rather than a morphological evolution (spherical micelles to cylinders to vesicles).

Published
2021

11. Evolution of the Nanostructure and Viscoelastic Properties of Nitrile Rubber upon Mechanical Rejuvenation and Physical Aging

Author

Gabriel E. Sanoja, Valérie Briand, Ingrid J. Paredes, Annie Brûlet, Bruno Bresson, Ayaskanta Sahu, Costantino Creton, Valentine Hervio, Sciences et Ingénierie de la Matière Molle (UMR 7615) (SIMM), Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), LLB - Matière molle et biophysique (MMB), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, New York University [New York] (NYU), NYU System (NYU), Safran Aerosystems, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
chemistry.chemical_classification, Nanostructure, Materials science, Polymers and Plastics, Organic Chemistry, 02 engineering and technology, Polymer, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Synthetic rubber, Viscoelasticity, 0104 chemical sciences, Inorganic Chemistry, Rheology, chemistry, Materials Chemistry, Copolymer, Stress relaxation, Composite material, 0210 nano-technology, Nitrile rubber, [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]
Abstract

International audience; Extending the mechanical lifetime of NBR (i.e., poly(acrylonitrile-co-butadiene)), a large-volume synthetic rubber, requires a better understanding of its structure–property relationships. We demonstrate that industrial-grade and uncross-linked NBR can be mechanically rejuvenated and physically aged due to an inhomogeneous distribution of monomers along the polymer chains. As opposed to its nonpolar SBR counterpart (i.e., poly(styrene-co-butadiene)), NBR experiences thermodynamic driving forces for microphase separation and kinetic barriers for processing like those of block copolymers. Extruding NBR at high temperature and shear results in a weakly microphase-separated nanostructure of low relaxation time and resistance to flow, whereas physically aging NBR leads to lamellar nanodomains, a more solid-like material, and delayed stress relaxation. This effect of rejuvenation and aging on the nanostructure and rheological properties of NBR has important consequences on processing and storage conditions, such as the formation of defect-free interfaces in multilayered parts by polymer interdiffusion.

Published
2021
Full Text
View/download PDF

12. Effect of Ligands on HP-Induced Unfolding and Oligomerization of β-Lactoglobulin

Author

Burkhard Annighöfer, Camille Loupiac, Simeon Minić, Gaston Hui Bon Hoa, Sophie Combet, Annie Brûlet, Djemel Hamdane, Arnaud Hélary, Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Laboratoire de Chimie des Processus Biologiques (LCPB), Collège de France (CdF (institution))-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM), Physico-Chimie de l'Aliment et du Vin (PCAV), Procédés Alimentaires et Microbiologiques [Dijon] (PAM), Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), LLB - Matière molle et biophysique (MMB), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement-Université Bourgogne Franche-Comté [COMUE] (UBFC)

Subjects
Whey protein, Protein Folding, [SDV]Life Sciences [q-bio], Biophysics, Ab initio, Lactoglobulins, 010402 general chemistry, Ligands, 01 natural sciences, 03 medical and health sciences, 0404 agricultural biotechnology, Animals, Denaturation (biochemistry), [SDV.BBM]Life Sciences [q-bio]/Biochemistry, Molecular Biology, Binding site, 030304 developmental biology, 0303 health sciences, Binding Sites, Chemistry, 04 agricultural and veterinary sciences, Articles, Ligand (biochemistry), 040401 food science, 0104 chemical sciences, Covalent bond, Unfolded protein response, Protein folding, Cattle, Hydrophobic and Hydrophilic Interactions
Abstract

To probe intermediate states during unfolding and oligomerization of proteins remains a major challenge. High pressure (HP) is a powerful tool for studying these problems, revealing subtle structural changes in proteins not accessible by other means of denaturation. Bovine β-lactoglobulin (BLG), the main whey protein, has a strong propensity to bind various bioactive molecules, such as retinol and resveratrol, two ligands with different affinity and binding sites. By combining in situ HP-small-angle neutron scattering (SANS) and HP-UV/visible absorption spectroscopy, we report the specific effects of these ligands on 3D conformational and local changes in BLG induced by HP. Depending on BLG concentration, two different unfolding mechanisms are observed in situ under pressures up to ~300 MPa, mediated by the formation of disulfide bonds: either a complete protein unfolding, from native dimers to Gaussian chains, or a partial unfolding with oligomerization in tetramers. Retinol, which has a high affinity for BLG hydrophobic cavity, significantly stabilizes BLG both in 3D and local environments, by shifting the onset of protein unfolding by ~100 MPa. Increasing temperature from 30 to 37°C enhances the hydrophobic stabilization effects of retinol. In contrast, resveratrol, which has a low binding affinity for site(s) on the surface of the BLG, does not induce any significant effect on the structural changes of BLG due to pressure. HP treatment back and forth up to ~300 MPa causes irreversible covalent oligomerization of BLG. Ab initio modeling of SANS shows that the oligomers formed from BLG/retinol complex are smaller and more elongated compared to BLG without ligand or in the presence of resveratrol. By combining HP-SANS and HP-UV/vis absorption spectroscopy, our strategy highlights the crucial role of BLG hydrophobic cavity and opens up new possibilities for the structural determination of HP-induced protein folding intermediates and irreversible oligomerization.STATEMENT OF SIGNIFICANCEHigh pressure (HP) is a powerful probe to access the intermediate states of proteins through subtle structural changes not accessible by other means of denaturation. Bovine β-lactoglobulin (BLG), the main whey protein, is able to bind various bioactive molecules, such as retinol and resveratrol, exhibiting different affinity and binding sites. By combining HP-small-angle neutron scattering and HP-UV/visible absorption spectroscopy, we highlight two different mechanisms during the unfolding and oligomerization of BLG depending on protein concentration. Above all, we show that retinol significantly prevents the unfolding and oligomerization of BLG, unlike resveratrol, emphasizing the crucial role of the hydrophobic cavity in BLG stabilization. Our strategy opens up new possibilities for the structural determination of protein intermediates and oligomers using HP.

Published
2020
Full Text
View/download PDF

13. Lamellar Bilayer to Fibril Structure Transformation of Tough Photonic Hydrogel under Elongation

Author

Takayuki Kurokawa, Annie Brûlet, Muhammad Ilyas, Riku Takahashi, J. Ping Gong, Alba Marcellan, Tasuku Nakajima, Kunpeng Cui, M. Anamul Haque, Hokkaido University [Sapporo, Japan], University of Dhaka, Hokkaido University of Science, Sciences et Ingénierie de la Matière Molle (UMR 7615) (SIMM), Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), LLB - Matière molle et biophysique (MMB), Laboratoire Léon Brillouin (LLB - UMR 12), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Toughness, Materials science, Polymers and Plastics, Bilayer, Organic Chemistry, technology, industry, and agriculture, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Fibril, 01 natural sciences, 0104 chemical sciences, Inorganic Chemistry, Micrometre, Self-healing hydrogels, Materials Chemistry, Lamellar structure, Elongation, Composite material, Deformation (engineering), 0210 nano-technology, [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]
Abstract

International audience; Synthetic hydrogels possessing both macroscopic anisotropic structure and toughness, which are analogous to the load-bearing bio-tissues such as muscles and tendons, are rarely available. Studying the molecular mechanism of tough and anisotropic hydrogel under deformation is beneficial to understand the load-deformation functions of soft bio-tissues. In this work, the deformation-induced structure transformation of a macroscopically anisotropic and tough hydrogel has been investigated to understand the role of structure evolution for enhanced toughness. At rest, the hydrogel possesses a well-defined hierarchical structure in which self-assembled nanometer thick lamellar bilayers are alternatively stacked in hundred nanometer thick hydrogel matrixes. Stretching along the lamellar direction induces structure transformation from lamellar bilayers to hierarchical fibrous structures aligned along the deformation axis. The generated hierarchical structures consist of micrometer thick fiber bundles made from nanometer thick fibrils analogous to tropo-collagen bundles or microfibrils of the tendon. The fibrous structure formed at large elongation is associated with damage and rupture of the bilayers, which underpins the molecular mechanism of the unique mechanical behaviors of the tough lamellar hydrogel.

Published
2020
Full Text
View/download PDF

14. Monitoring food structure during digestion using small-angle scattering and imaging techniques

Author

Evelyne Lutton, Thomas Bizien, Frédéric Jamme, Adeline Boire, Jade Pasquier, François Boué, Annie Brûlet, Javier Pérez, LLB - Matière molle et biophysique (MMB), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Génie et Microbiologie des Procédés Alimentaires (GMPA), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Unité de recherche sur les Biopolymères, Interactions Assemblages (BIA), Institut National de la Recherche Agronomique (INRA), INRA (CEPIA Division), SOLEIL, LLB, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, and Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)

Subjects
Materials science, Kinetics, Small angle neutron scattering, FOS: Physical sciences, 02 engineering and technology, Neutron scattering, Condensed Matter - Soft Condensed Matter, 010402 general chemistry, 01 natural sciences, law.invention, Plant protein, Colloid and Surface Chemistry, law, Elastic modulus, Gel, Small angle X ray scattering, Scattering, 021001 nanoscience & nanotechnology, Synchrotron, 0104 chemical sciences, Brillouin zone, [CHIM.POLY]Chemical Sciences/Polymers, Chemical physics, Deep UV synchrotron radiation fluorescence microscopy, Soft Condensed Matter (cond-mat.soft), Digestion, Small-angle scattering, 0210 nano-technology, [SDV.AEN]Life Sciences [q-bio]/Food and Nutrition, [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]
Abstract

Various studies have shown that food structure has an impact on digestion kinetics. We focus here on the effects of gastric and intestinal enzymes (in-vitro digestion) on two canola seed storage proteins, napin and cruciferin. To monitor structure effect we conducted experiments on gels of these proteins at different pHs, yielding different structures and elastic modulus. What is new is to get information on the mechanisms at the lowest scales, using imaging and radiation scattering at large facilities: Synchrotron fluorescence microscopy, X-Ray scattering, at SOLEIL synchrotron, and Small-Angle Neutron Scattering, at Laboratoire Leon Brillouin reactor. We can identify the mechanisms at each step and in two distinct scale ranges, observed simultaneously, the one of the individual protein scale and the one of the structure connectivity: • during gelation individual canola proteins are not deeply modified in comparison with their state in solution ; larger scale gel heterogeneity appears due to connectivity or aggregation • in the gastric step (up to 40 min): ○ at short scale (large q) we see that the proteins disintegration is much slowed down in gels than in solutions, particularly in the gastric phase; ○ at larger scales (low q), we see that the gel structure is also self-resistant to the action of the enzyme (pepsin). • in the intestinal step, such kinetics differences hold until major disintegration after no more than 15 min.

Published
2020
Full Text
View/download PDF

15. Large and Giant Unilamellar Vesicle(s) Obtained by Self-Assembly of Poly(dimethylsiloxane)-b-poly(ethylene oxide) Diblock Copolymers, Membrane Properties and Preliminary Investigation of their Ability to Form Hybrid Polymer/Lipid Vesicles

Author

Marc Schmutz, Stéphane Carlotti, Martin Fauquignon, Jean-François Le Meins, Annie Brûlet, Emmanuel Ibarboure, Laboratoire de Chimie des Polymères Organiques (LCPO), Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Team 3 LCPO : Polymer Self-Assembly & Life Sciences, Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Team 1 LCPO : Polymerization Catalyses & Engineering, Groupe Diffusion petits angles (GDPA), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Institut Charles Sadron (ICS), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Sandre, Olivier, Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC), Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Institut Rayonnement Matière de Saclay (IRAMIS), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Matériaux et nanosciences d'Alsace (FMNGE), and Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM.POLY] Chemical Sciences/Polymers, Materials science, Polymers and Plastics, Block copolymer, 02 engineering and technology, macromolecular substances, 010402 general chemistry, 01 natural sciences, Micropipette, Giant Hybrid Unilamellar Vesicles, Dynamic light scattering, Copolymer, Static light scattering, chemistry.chemical_classification, Vesicle, self- assembly, technology, industry, and agriculture, self-assembly, General Chemistry, Polymer, 021001 nanoscience & nanotechnology, Small-angle neutron scattering, 0104 chemical sciences, [PHYS.COND.CM-SCM] Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], Phospholipid, [CHIM.POLY]Chemical Sciences/Polymers, Chemical engineering, Polymerization, chemistry, Polymersome, 0210 nano-technology, [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]
Abstract

In the emerging field of hybrid polymer/lipid vesicles, relatively few copolymers have been evaluated regarding their ability to form these structures and the resulting membrane properties have been scarcely studied. Here, we present the synthesis and self-assembly in solution of poly(dimethylsiloxane)-block-poly(ethylene oxide) diblock copolymers (PDMS-b-PEO). A library of different PDMS-b-PEO diblock copolymers was synthesized using ring-opening polymerization of hexamethylcyclotrisiloxane (D3) and further coupling with PEO chains via click chemistry. Self-assembly of the copolymers in water was studied using Dynamic Light Scattering (DLS), Static Light Scattering (SLS), Small Angle Neutron Scattering (SANS), and Cryo-Transmission Electron Microscopy (Cryo-TEM). Giant polymersomes obtained by electroformation present high toughness compared to those obtained from triblock copolymer in previous studies, for similar membrane thickness. Interestingly, these copolymers can be associated to phospholipids to form Giant Hybrid Unilamellar Vesicles (GHUV), preliminary investigations of their mechanical properties show that tough hybrid vesicles can be obtained.

Published
2019
Full Text
View/download PDF

16. Large and Giant Unilamellar Vesicle(s) Obtained by Self-Assembly of Poly(dimethylsiloxane)

Author

Martin, Fauquignon, Emmanuel, Ibarboure, Stéphane, Carlotti, Annie, Brûlet, Marc, Schmutz, and Jean-François, Le Meins

Subjects
giant hybrid unilamellar vesicles, technology, industry, and agriculture, block copolymer, macromolecular substances, micropipette, self-assembly, Article, phospholipid
Abstract

In the emerging field of hybrid polymer/lipid vesicles, relatively few copolymers have been evaluated regarding their ability to form these structures and the resulting membrane properties have been scarcely studied. Here, we present the synthesis and self-assembly in solution of poly(dimethylsiloxane)-block-poly(ethylene oxide) diblock copolymers (PDMS-b-PEO). A library of different PDMS-b-PEO diblock copolymers was synthesized using ring-opening polymerization of hexamethylcyclotrisiloxane (D3) and further coupling with PEO chains via click chemistry. Self-assembly of the copolymers in water was studied using Dynamic Light Scattering (DLS), Static Light Scattering (SLS), Small Angle Neutron Scattering (SANS), and Cryo-Transmission Electron Microscopy (Cryo-TEM). Giant polymersomes obtained by electroformation present high toughness compared to those obtained from triblock copolymer in previous studies, for similar membrane thickness. Interestingly, these copolymers can be associated to phospholipids to form Giant Hybrid Unilamellar Vesicles (GHUV); preliminary investigations of their mechanical properties show that tough hybrid vesicles can be obtained.

Published
2019

17. Self-Assembly of PEG

Author

Coralie, Lebleu, Laura, Rodrigues, Jean-Michel, Guigner, Annie, Brûlet, Elisabeth, Garanger, and Sébastien, Lecommandoux

Abstract

Poly(ethylene glycol)

Published
2019

18. Embedding of superparamagnetic iron oxide nanoparticles into membranes of well-defined poly(ethylene oxide)-block-poly(ε-caprolactone) nanoscale magnetovesicles as ultrasensitive MRI probes of membrane bio-degradation

Author

Dimitri Stanicki, Robert N. Muller, Sophie Laurent, Annie Brûlet, Adeline Hannecart, Christophe Schatz, Sébastien Lecommandoux, Luce Vander Elst, Olivier Sandre, NMR Laboratory, Université de Mons, Université de Mons (UMons), University of Mons [Belgium] (UMONS), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Chimie des Polymères Organiques (LCPO), Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Team 3 LCPO : Polymer Self-Assembly & Life Sciences, Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), CPER CAMPUSB project funded by the French state and the Région Nouvelle Aquitaine, ARC program, ENCITE program, Wallonia Region, Interuniversity Attraction Poles of the Belgian Federal Science Policy Office, ANR-13-BS08-0017,MagnetoChemoBlast,Magnéto-Chimiothérapie : Modélisation de la Délivrance Induite par Champ Magnétique Radiofréquence d'Anticancéreux par des Nano-Vésicules Polymères et Suivi par IRM d'un Modèle de Glioblastome(2013), European Project: COST Action TD1402,RADIOMAG, NMR and Molecular Imaging Laboratory [Mons], Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC), and Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)

Subjects
Polymersomes, Materials science, Magnetic nanocarriers, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, Polyesters, Biomedical Engineering, Oxide, Nanoparticle, 02 engineering and technology, Magnetic nanoparticles MNPs, MRI-guided therapy, 010402 general chemistry, 01 natural sciences, Ferric Compounds, Proof of Concept Study, Biodegradable polymers, Light scattering, chemistry.chemical_compound, Drug Delivery Systems, Dynamic light scattering, Polymer vesicles, MRI contrast agents, General Materials Science, Magnetite Nanoparticles, chemistry.chemical_classification, Hydrolysis, technology, industry, and agriculture, Membranes, Artificial, General Chemistry, General Medicine, Polymer, [CHIM.MATE]Chemical Sciences/Material chemistry, Hydrogen-Ion Concentration, 021001 nanoscience & nanotechnology, equipment and supplies, Small-angle neutron scattering, Magnetic Resonance Imaging, 0104 chemical sciences, Polycaprolactone, Acidolysis, Membrane, [CHIM.POLY]Chemical Sciences/Polymers, chemistry, Chemical engineering, Polymersome, [SDV.IB]Life Sciences [q-bio]/Bioengineering, Drug Monitoring, 0210 nano-technology, [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]
Abstract

International audience; The present study reports the preparation of poly(ethylene oxide)-block-poly(ε-caprolactone) (PEO-b-PCL) polymer vesicles via a nanoprecipitation method and the loading of two different size hydrophobically coated ultrasmall superparamagnetic iron oxide (USPIO) nanoparticles (magnetic core size of 4.2 nm and 7.6 nm) into the membrane of these nanovesicles, whose thickness was measured precisely by small angle neutron scattering (SANS). Spherical nano-assemblies with a high USPIO payload and a diameter close to 150 nm were obtained as confirmed by dynamic light scattering (DLS), transmission electron microscopy (TEM) and cryo-TEM. Vesicular structure of these hybrid nano-assemblies was confirmed by multi-angle light scattering (MALS) measurements. Their magnetic properties were evaluated by T1 and T2 measurements (20 and 60 MHz) and by nuclear magnetic relaxation dispersion (NMRD) profiles. The size of USPIO entrapped in the membranes of PEO-b-PCL vesicles has a strong impact on their magnetic properties. It affects both their longitudinal and their transverse relaxivities and thus their magnetic resonance imaging (MRI) sensitivity. Acid-catalyzed hydrolysis of PCL membrane also influences their relaxivities as shown by measurements carried out at pH 7 vs. pH 5. This property was used to monitor the membrane hydrolytic degradation in vitro, as a proof of concept of potential monitoring of a drug delivery by nanomedicines in vivo and non-invasively, by MRI.

Published
2019
Full Text
View/download PDF

19. Porosity evolution of expanded vermiculite under pressure: the effect of pre-compaction

Author

A.N. Nguyen, Alfonso San-Miguel, Annie Brûlet, Sylvie Le Floch, Laurent Duclaux, Félix Balima, Laurence Reinert, Isabelle Daniel, Laurent Gremillard, Vittoria Pischedda, (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Spectroscopies optiques des matériaux verres, amorphes et à nanoparticules (SOPRANO), Laboratoire LCME / Equipe Chimie Verte (LCME_CV), Laboratoire de Chimie Moléculaire et Environnement (LCME), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), University of Sciences [Ho Chi Minh City] (HCMC), Ho Chi Minh City University of Science (HCMUS), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), LLB - Matière molle et biophysique (MMB), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Matériaux, ingénierie et science [Villeurbanne] (MATEIS), Université de Lyon-Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), ANR-08-MAPR-0011,CELAJOAS,ComposÉs LAmellaires pour les JOints en Applications Sévères(2008), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon

Subjects
Materials science, General Chemical Engineering, General Engineering, Compaction, General Physics and Astronomy, 02 engineering and technology, [CHIM.MATE]Chemical Sciences/Material chemistry, Vermiculite, 021001 nanoscience & nanotechnology, 01 natural sciences, Fractal dimension, 010305 fluids & plasmas, Stress (mechanics), 0103 physical sciences, General Earth and Planetary Sciences, General Materials Science, Lamellar structure, Texture (crystalline), Composite material, 0210 nano-technology, Anisotropy, Porosity, General Environmental Science
Abstract

International audience; The evolution of the pore structure of compressed expanded vermiculite was investigated in situ under uniaxial stress up to 3200 bar using small-angle neutron and X-ray scattering. The studied samples have a lamellar texture in which the presence of oriented oblate pores was revealed by the anisotropic small-angle scattering patterns. The initial pore size distribution and the mechanical behaviour of the pellets at working pressure conditions are strongly related to the applied initial stresses used to pre-compact the vermiculite powder. Our study shows that the porous structure of the pellets was not modified under compression up to the pre-compaction pressure. Higher densification is associated with increasing anisotropy of the pore–matrix interface structure. The pore–matrix interface could be described with fractal geometry. The stress dependence of the system fractal dimension, apparent specific surface area and total porosity was determined and related to the meso- and macropore evolution under uniaxial stress.

Published
2019
Full Text
View/download PDF

20. Versatile oligo(ethylene glycol)-based biocompatible microgels for loading/release of active bio(macro)molecules

Author

Annie Brûlet, Laurent Billon, Kamel Chougrani, Garbiñe Elorriaga Aguirre, Valérie Alard, Elise Deniau, Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux (IPREM), Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Parfums et Cosmétiques, LVMH Moët Hennessy Louis Vuitton, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay

Subjects
Ethylene Glycol, Macromolecular Substances, Ethylene glycol dimethacrylate, Ether, Biocompatible Materials, 02 engineering and technology, Cosmetics, 010402 general chemistry, 01 natural sciences, Hydrophobic effect, chemistry.chemical_compound, Colloid and Surface Chemistry, Stimuli-responsive microgels, Delivery systems, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, medicine, Molecule, Humans, Physical and Theoretical Chemistry, Microstructure, Cosmetic active molecules, Surfaces and Interfaces, General Medicine, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Cross-Linking Reagents, [CHIM.POLY]Chemical Sciences/Polymers, chemistry, Chemical engineering, Proton NMR, Swelling, medicine.symptom, 0210 nano-technology, Ethylene glycol, Gels, Biotechnology, Macromolecule
Abstract

International audience; The present study aims in the understanding of the effect of oligo(ethylene glycol)-based biocompatible microgels inner structure on the encapsulation/release mechanisms of different types of cosmetic active molecules. For that, multi-responsive microgels were synthesized using three types of cross-linkers: ethylene glycol dimethacrylate (EGDMA), oligo(ethylene glycol) diacrylate (OEGDA) and N,N-methylenebisacrylamide (MBA). The inner morphology of the microgels synthesized was studied by 1H-nuclear magnetic resonance (1H NMR) and small-angle neutron scattering (SANS) techniques and no effect of cross-linker type on microgel microstructure was observed in the case of analysing purified microgel dispersions. Moreover, all the microgels synthesized presented conventional swelling/de-swelling behavior as a function of temperature and pH. Two hydrophobic, one hydrophilic, and one macromolecule as cosmetic active molecules were effectively loaded into different microgel particles via hydrophobic interactions and hydrogen-bonding interactions between −OH groups of active molecules and ether oxygens of different microgel particles. Their release profiles as a function of cross-linker type used and encapsulated amounts were studied by Peppas-Sahlin model. No effect of the cross-linker type was observed due to the similar inner structure of all the microgels synthesized.

Published
2019
Full Text
View/download PDF

21. End-chain fluorination of polyesters favors perfluorooctyl bromide encapsulation into echogenic PEGylated nanocapsules

Author

Laurence Moine, Alexis Chennevière, Sophie Houvenagel, Camille Dejean, Olivier Couture, Guilherme Fadel Picheth, Nicolas Huang, Nicolas Tsapis, and Annie Brûlet

Subjects
chemistry.chemical_classification, Materials science, Polymers and Plastics, Organic Chemistry, Echogenicity, Bioengineering, 02 engineering and technology, Polymer, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Biochemistry, Small-angle neutron scattering, Nanocapsules, 0104 chemical sciences, Surface tension, Polyester, chemistry.chemical_compound, chemistry, Chemical engineering, Bromide, Organic chemistry, 0210 nano-technology, Ethylene glycol
Abstract

Perfluorinated end-capped polylactides (PLAs) with various perfluorinated chain lengths from C3F7 to C13F27 were synthesized and formulated into PEGylated nanocapsules of perfluorooctyl bromide (PFOB) to be used as ultrasound contrast agents (UCAs). We show that the perfluorinated end groups do not reduce the interfacial tension between PFOB and the organic solvent used during formulation and do not allow a significant reduction of shell thickness (Small angle neutron scattering (SANS) experiments). However, the PFOB encapsulation efficiency increases with the fluorinated chain length until C8F17. This suggests the possible presence of favorable fluorophilic interactions between PFOB and perfluorinated end groups. In addition, nanocapsules formulated with different fluorinated polymers do not promote any specific toxicity in vitro compared to non-fluorinated PLAs. Ultrasound imaging performed on samples presenting the lowest thickness values, namely nanocapsules made from 50% PLA-C6F13/50% polylactide-b-poly(ethylene glycol) (PLA-PEG) and pure PLA-PEG nanocapsules, shows that fluorinated nanocapsules exhibit a higher ultrasound contrast enhancement in vitro most probably thanks to the higher PFOB content and density arising from polymer fluorination. This highlights the benefit of fluorination for improving the echogenicity of nano-sized ultrasound contrast agents.

Published
2017
Full Text
View/download PDF

22. PEGylated nanocapsules of perfluorooctyl bromide: Mechanism of formation, influence of polymer concentration on morphology and mechanical properties

Author

Estelle Morvan, Odile Diou, Gérard Pehau-Arnaudet, Nicolas Taulier, Elias Fattal, Annie Brûlet, Romain Berti, Ksenia Astafyeva, and Nicolas Tsapis

Subjects
Materials science, Polymers, Surface Properties, Nanotechnology, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Nanocapsules, Polyethylene Glycols, law.invention, chemistry.chemical_compound, Colloid and Surface Chemistry, law, Bromide, High polymer, Dewetting, Physical and Theoretical Chemistry, Polyglactin 910, chemistry.chemical_classification, Fluorocarbons, Water, Surfaces and Interfaces, General Medicine, Polymer, 021001 nanoscience & nanotechnology, Small-angle neutron scattering, Hydrocarbons, Brominated, 0104 chemical sciences, chemistry, Chemical engineering, Emulsions, Electron microscope, 0210 nano-technology, Ethylene glycol, Biotechnology
Abstract

PEGylated nanocapsules containing a liquid core of perfluorooctyl bromide (PFOB) were formulated by an emulsion-evaporation process to be further used as ultrasound contrast agents (UCAs). In an attempt to modulate their acoustic response, related to their shell thickness-to-radius ratio, the initial concentration of polymer was varied in the formulation. Indeed, thinner shells may lead to higher echogenicity. PEGylated nanocapsules morphology was studied by electron microscopy, Small Angle Neutron Scattering and 19F NMR spectroscopy and related to their mechanical properties to allow a better understanding of their mechanism of formation. We show that the variation of polymer concentration in the formulation impacts the formation mechanism of nanocapsules, and consequently their morphology and mechanical properties. Using low concentration of Poly(ethylene glycol)-b-poly( dl -lactide-co-glycolide) (PLGA-b-PEG), it is impossible to reduce the shell thickness of the UCA, most probably due to dewetting of the polymer layer at the PFOB/water interface. This leads to the coexistence of thick shells along with free PFOB droplets. On the other hand, for high polymer concentration, PEGylated nanocapsules with thick shells were produced with high encapsulation efficiency.

Published
2016
Full Text
View/download PDF

23. Self-Assembly of Stimuli-Responsive Biohybrid Synthetic-b-Recombinant Block Copolypeptides

Author

Sébastien Lecommandoux, Anne-Laure Wirotius, Gaëlle Le Fer, Elisabeth Garanger, Annie Brûlet, Laboratoire de Chimie des Polymères Organiques (LCPO), Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Team 3 LCPO : Polymer Self-Assembly & Life Sciences, Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Team 1 LCPO : Polymerization Catalyses & Engineering, Groupe Diffusion petits angles (GDPA), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC), Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Institut Rayonnement Matière de Saclay (IRAMIS)

Subjects
Circular dichroism, Polymers and Plastics, Small angle neutron scattering, poly(L-glutamic acid), Nanoparticle, Bioengineering, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Micelle, Phase Transition, Polymerization, Biomaterials, Phase (matter), elastin-like polypeptides, Materials Chemistry, Transition Temperature, Static light scattering, Poly(glutamic acid), Micelles, thermoresponsive diblock copolypeptides, Biohybrids, Chemistry, self-assembly, [CHIM.MATE]Chemical Sciences/Material chemistry, Stimuli Responsive Polymers, Recombinant polypeptides, 021001 nanoscience & nanotechnology, Small-angle neutron scattering, Peptide Fragments, Recombinant Proteins, 0104 chemical sciences, Elastin, Synthetic polypeptides, Crystallography, [CHIM.POLY]Chemical Sciences/Polymers, Polyglutamic Acid, nanoparticles, Turbidimetry, Self-assembly, 0210 nano-technology, [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]
Abstract

International audience; The synthesis and original thermoresponsive behavior of hybrid diblock copolypeptides composed of synthetic and recombinant polypeptides are herein reported. A thermoresponsive recombinant elastin-like polypeptide was used as a macroinitiator to synthesize a range of poly(L-glutamic acid)-block-elastin-like polypeptide (PGlu-b-ELP) diblock copoly-peptides with variable PGlu block lengths. Their temperature-triggered self-assembly in water and in phosphate-buffered saline (PBS) was investigated at the macroscopic scale using complementary techniques such as turbidimetry, dynamic and static light scattering, small-angle neutron scattering, and at the molecular scale by 1 H NMR and circular dichroism (CD). In deionized water, PGlu-b-ELP copolypeptides showed one transition from free soluble chains below the transition temperature (Tt) of the ELP block to macroscopic aggregates above the Tt. In contrast, in PBS, four successive regimes were observed upon increasing temperature: below the Tt , copolypeptides were soluble, above the Tt , large aggregates appeared and fell apart into discrete and defined spherical nanoparticles at a temperature named critical micellization temperature (CMT), before finally reaching an equilibrium. During the last regime, neutron scattering experiments revealed that the micelle-like structures underwent a densification step and expelled water from their core. In addition, 1H NMR and CD experiments revealed, in deionized water, the formation of type II β-turns into the ELP block upon temperature increase. These β-turns are known to participate in the intrinsic thermoresponsive behavior of the ELPs. In contrast, in PBS, circular dichroism measurements showed an attenuation of folded structure during the self-assembly phase, leading to less cohesive aggregates able to reorganize into nanoparticles at the CMT.

Published
2019
Full Text
View/download PDF

24. Self-Assembly of PEG-b-PTMC Copolymers: Micelles and Polymersomes Size Control

Author

Laura Rodrigues, Annie Brûlet, Jean-Michel Guigner, Coralie Lebleu, Sébastien Lecommandoux, Elisabeth Garanger, Laboratoire de Chimie des Polymères Organiques (LCPO), Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Team 3 LCPO : Polymer Self-Assembly & Life Sciences, Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), LLB - Matière molle et biophysique (MMB), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Centre National de la Recherche Scientifique (CNRS), TEAM 3 LCPO, Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux (Bordeaux INP)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC), and Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)

Subjects
Polymersomes, Materials science, Dispersity, Microfluidics, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Micelle, chemistry.chemical_compound, Electrochemistry, Copolymer, General Materials Science, Ring Opening Polymerization, Spectroscopy, Block Copolymers, Molar mass, Surfaces and Interfaces, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, [CHIM.POLY]Chemical Sciences/Polymers, Chemical engineering, chemistry, Polymerization, Polymersome, Trimethylene carbonate, 0210 nano-technology, Nanoprecipitation, Ethylene glycol, [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]
Abstract

International audience; Poly(ethylene glycol)45-b-poly(trimethylene carbonate)n PEG45-b-PTMCn diblock copolymers were synthesized with five different PTMC degrees of polymerization (n = 38, 96, 144, 170, 332) and their self-assembly properties in water were studied using a manual nanoprecipitation procedure. We confirmed that the copolymer’s hydrophilic weight fraction (fPEG) is controlling nanoparticles morphology. We determined that the PEG45-b-PTMC96 with fPEG ≈ 17% is the optimal hydrophilic fraction for the stabilization of well-defined unilamellar vesicles with a membrane thickness of δ ≈ 14.6 nm. Maintaining this fraction constant and modulating the overall molar mass of the block copolymers allowed the establishment of a power law of which provides a robust correlation between the molar mass of PTMC and vesicles’ membrane thickness. Finally, we proved that controlling nanoprecipitation’s conditions by microfluidics allowed fine-tuning and control of the nanoparticles size and polydispersity index while maintaining their shape with a perfect batch-to-batch reproducibility.

Published
2019
Full Text
View/download PDF

25. Comb-Like Fluorophilic-Lipophilic-Hydrophilic Polymers for Nanocapsules as Ultrasound Contrast Agents

Author

Nicolas Huang, Nicolas Tsapis, Laurence Moine, Olivier Couture, Guilherme Fadel Picheth, Sophie Houvenagel, Annie Brûlet, Vincent Faugeras, Camille Dejean, Alexis Chennevière, Institut Galien Paris-Sud (IGPS), Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Polymers and Plastics, Fluorine Compounds, Contrast Media, Bioengineering, macromolecular substances, 02 engineering and technology, 010402 general chemistry, Methacrylate, 01 natural sciences, Nanocapsules, Cell Line, Polyethylene Glycols, Biomaterials, chemistry.chemical_compound, Mice, Materials Chemistry, Copolymer, Human Umbilical Vein Endothelial Cells, Animals, Humans, Ultrasonography, chemistry.chemical_classification, Atom-transfer radical-polymerization, Macrophages, technology, industry, and agriculture, Polymer, Permeation, 021001 nanoscience & nanotechnology, 0104 chemical sciences, [CHIM.POLY]Chemical Sciences/Polymers, Polymerization, chemistry, Chemical engineering, Acrylates, 0210 nano-technology, Ethylene glycol
Abstract

International audience; Imaging the enhanced permeation and retention effect by ultrasound is hindered by the large size of commercial ultrasound contrast agents (UCAs). To obtain nanosized UCAs, triblock copolymers of poly(ethylene glycol)-polylactide-poly(1H,1H,2H,2H-heptadecafluorodecyl methacrylate) (PEG-PLA-PFMA) with distinct numbers of perfluorinated pendant chains (5, 10, or 20) are synthesized by a combination of ring-opening polymerization and atom transfer radical polymerization. Nanocapsules (NCs) containing perfluorooctyl bromide (PFOB) intended as UCAs are obtained with a 2-fold increase in PFOB encapsulation efficiency in fluorinated NCs as compared with plain PEG-PLA NCs thanks to fluorous interactions. NC morphology is strongly influenced by the number of perfluorinated chains and the amount of polymer used for formulation, leading to peculiar capsules with several PFOB cores at high PEG-PLA-PFMA 20 amount and single-cored NCs with a thinner shell at low fluorinated polymer amount, as confirmed by small-angle neutron scattering. Finally, fluorinated NCs yield higher in vitro ultrasound signal compared with PEG-PLA NCs, and no in vitro cytotoxicity is induced by fluorinated polymers and their degradation products. Our results highlight the benefit of adding comb-like fluorinated blocks in PEG-PLA polymers to modify the nanostructure and enhance the echogenicity of nanocapsules intended as UCAs.

Published
2018
Full Text
View/download PDF

26. Cationic Thermoresponsive Poly( N -vinylcaprolactam) Microgels Synthesized by Emulsion Polymerization Using a Reactive Cationic Macro-RAFT Agent

Author

Elise Deniau, Jacqueline Forcada, Annie Brûlet, Laura Etchenausia, Maud Save, Institut des sciences analytiques et de physico-chimie pour l'environnement et les materiaux (IPREM), Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, University of the Basque Country/Euskal Herriko Unibertsitatea (UPV/EHU), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Polymers and Plastics, Emulsion polymerization, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Chloride, Inorganic Chemistry, chemistry.chemical_compound, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Materials Chemistry, medicine, Poly-N-vinylcaprolactam, chemistry.chemical_classification, Chemistry, Organic Chemistry, Cationic polymerization, Raft, Polymer, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, [CHIM.POLY]Chemical Sciences/Polymers, Chemical engineering, Polymerization, Xanthate, 0210 nano-technology, medicine.drug
Abstract

International audience; A series of reactive poly([2-(acryloyloxy)ethyl]trimethylammonium chloride) (P(AETAC)) cationic polymers with varying degrees of polymerization were synthesized by RAFT/MADIX polymerization and investigated as stabilizers for the emulsion polymerization of N-vinylcaprolactam (PVCL) in the presence of a cross-linker. It was demonstrated that the xanthate chain end of the cationic P(AETAC-X) polymers played a crucial role to produce stable cationic PVCL-based microgels at higher initial solids content (5–10 wt %) than usually reported for the synthesis of PVCL microgels. The thermoresponsive PVCL microgels with cationic shell undergo a reversible volume shrinkage upon heating in the absence of any hysteresis in accordance with the narrow particle size distribution. The values of the volume phase transition temperature ranged between 28 and 30 °C for the microgels synthesized using 4 and 8 wt % of P(AETAC-X) based on VCL. The presence of a cationic outer shell onto the microgels was evidenced by the positive values of the electrophoretic mobility. The swelling behavior of the thermoresponsive microgel particles can be tuned by playing on two synthesis variables which are the initial solids content and the content of P(AETAC-X) macro-RAFT stabilizer. Furthermore, the inner structure of the synthesized microgels was probed by transverse relaxation nuclear magnetic resonance (T2 NMR) and small-angle neutron scattering (SANS) measurements. The fit of T2 NMR data confirmed a core–shell morphology with different cross-linking density in PVCL microgels. Through the determination of the network mesh size, SANS was suitable to explain the increase of the values of the PVCL microgel swelling ratios by increasing the initial solids content of their synthesis.

Published
2018
Full Text
View/download PDF

27. On the design and experimental realization of a multislit-based very small angle neutron scattering instrument at the European Spallation Source

Author

Sylvain Desert, Pascal Lavie, Jacques Jestin, Patrice Permingeat, Vincent Thevenot, Sohrab Abbas, and Annie Brûlet

Subjects
Physics, Scattering, business.industry, Collimator, Neutron radiation, Neutron scattering, Small-angle neutron scattering, General Biochemistry, Genetics and Molecular Biology, Neutron time-of-flight scattering, law.invention, Optics, law, Spallation, business, Scaling
Abstract

This article reports the design of a versatile multislit-based very small angle neutron scattering (VSANS) instrument working either as a dedicated instrument or as an add-on for any small-angle neutron scattering machine like the proposed SANS instrument, SKADI, at the future European Spallation Source. The use of multiple slits as a VSANS collimator for the time-of-flight techniques has been validated using McStas simulations. Various instrument configurations to achieve different minimum wavevector transfers in scattering experiments are proposed. The flexibility of the multislit VSANS instrument concept is demonstrated by showing the possibility of instrument length scaling for the first time, allowing access to varying minimum wavevector transfers with the same multislit setup. These options can provide smooth access to minimum wavevector transfers lower than ∼4 × 10−5 Å−1 and an overlapping of wavevector coverage with normal SANS mode, e.g. with the SKADI wavevector range of 10−3–1.1 Å−1. Such an angularly well defined and intense neutron beam will allow faster SANS studies of objects larger than 1 µm. Calculations have also been carried out for a radial collimator as an alternative to the multislit collimator setup. This extends the SANS Q range by an order of magnitude to 1 × 10−4 Å−1 with much simpler alignment. The multislit idea has been realized experimentally by building a prototype at Laboratoire Leon Brillouin, Saclay, with cross-talk-free geometry. Feasibility studies were carried out by making VSANS measurements with single- and multislit collimators, and the results are compared with multiple-pinhole geometry using classical SANS analysis tools.

Published
2015
Full Text
View/download PDF

28. Probing structure in submicronic aqueous assemblies of emulsified microemulsions and charged spherical colloids using SANS and cryo-TEM

Author

Thibault Dégousée, Jéril Degrouard, Annie Brûlet, Anniina Salonen, and François Muller

Subjects
Coalescence (physics), endocrine system, Materials science, Aqueous solution, digestive, oral, and skin physiology, Cationic polymerization, Nanotechnology, Neutron scattering, complex mixtures, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Biomaterials, Colloid, Colloid and Surface Chemistry, Pulmonary surfactant, Chemical engineering, Transmission electron microscopy, Microemulsion
Abstract

The spatial distribution of charged spherical colloids when used as stabilizers of phytantriol-based emulsified microemulsions (EME, L2 symmetry group) is investigated. The coverage of the lipid-based mesophases by the colloids is monitored using small-angle neutron scattering (SANS) in contrast matching conditions and visualized using cryogenic transmission electron microscopy (cryo-TEM) imaging. The results demonstrate that, despite the stability of the emulsion droplets, very few colloids are ever found on the droplets. The stability of the EMEs is suggested to arise from the very slow ripening rates combined with punctual repulsion against coalescence from the isolated charged colloids on the bigger droplet surfaces. We show the possibility of creating a dense cover around the droplets by partially hydrophobizing the colloids by adsorbing a cationic surfactant on their surface. This opens up the possibilities for further modulation of the colloidal coverage in these systems. This is an interesting route for the design of new Colloid-ISAsome assemblies in which dense protective armors could be advantageous such as controlled delivery.

Published
2015
Full Text
View/download PDF

29. How necklace pearls evolve in hydrophobic polyelectrolyte chains under good solvent addition: A sans study of the conformation

Author

Souha Ben Mahmoud, François Boué, Annie Brûlet, Wafa Essafi, Institut National de Recherche et d'Analyse Physico-Chimique (INRAP), Institut National des Sciences Appliquées et de Technologie (INSAT), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Génie et Microbiologie des Procédés Alimentaires (GMPA), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Tunisian Ministry of Higher Education and Scientific Research, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Polymers and Plastics, [SDV]Life Sciences [q-bio], 02 engineering and technology, Neutron scattering, 010402 general chemistry, 01 natural sciences, Inorganic Chemistry, chemistry.chemical_compound, Chain (algebraic topology), [SDV.IDA]Life Sciences [q-bio]/Food engineering, Materials Chemistry, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, Tetrahydrofuran, chemistry.chemical_classification, Organic Chemistry, Form factor (quantum field theory), Polymer, 021001 nanoscience & nanotechnology, Polyelectrolyte, 0104 chemical sciences, Solvent, Crystallography, chemistry, Polystyrene, 0210 nano-technology
Abstract

International audience; The chain conformation in sulfonated polystyrene PSSNa of a degree of sulfonation 0.34

Published
2018
Full Text
View/download PDF

30. Insight into neutron focusing: the out-of-focus condition

Author

Sylvain Desert, David F. R. Mildner, Annie Brûlet, and Boualem Hammouda

Subjects
Physics, Bonner sphere, business.industry, Astrophysics::High Energy Astrophysical Phenomena, Neutron diffraction, Neutron scattering, Small-angle neutron scattering, General Biochemistry, Genetics and Molecular Biology, Neutron time-of-flight scattering, Optics, Neutron detection, Neutron, Neutron reflectometry, business
Abstract

Neutron focusing leads to significant gains in flux-on-sample in small-angle neutron scattering and very small angle neutron scattering instruments. Understanding the out-of-focus condition is necessary for less than optimal conditions such as for short instruments and low neutron wavelengths. Neutron focusing is investigated using a three-pronged approach. The three methods are analytical calculations, resolution measurements and computer simulations. A source aperture containing a single small-size hole and a sample aperture containing multiple holes are used to produce multiple spots on the high-resolution neutron detector. Lens focusing elongates off-axis spots in the radial direction. The standard deviation for the size of each spot is estimated using these three approaches. Varying parameters include the neutron wavelength, the number of focusing lenses and the location of holes on the sample aperture. Enough agreement for the standard deviation of the individual neutron beams was found between the calculations and the measurements to give confidence in this approach. Good agreement was found between the standard deviations obtained from calculations and simulations as well. Excellent agreement was found for the mean location of these individual spots.

Published
2013
Full Text
View/download PDF

31. Thermoresponsive Toughening in LCST-Type Hydrogels with Opposite Topology: From Structure to Fracture Properties

Author

Nicolas Sanson, Annie Brûlet, Alba Marcellan, Cécile Mussault, Hui Guo, Dominique Hourdet, Sciences et Ingénierie de la Matière Molle (SIMM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay

Subjects
Phase transition, Materials science, Polymers and Plastics, nanostructure, 02 engineering and technology, Neutron scattering, 010402 general chemistry, Topology, 01 natural sciences, Lower critical solution temperature, Inorganic Chemistry, chemistry.chemical_compound, Ultimate tensile strength, Materials Chemistry, poly(N-isopropylacrylamide), hydrogels, chemistry.chemical_classification, responsive toughening, Isochoric process, Organic Chemistry, Polymer, 021001 nanoscience & nanotechnology, crack bifurcation, 0104 chemical sciences, chemistry, Self-healing hydrogels, Poly(N-isopropylacrylamide), 0210 nano-technology, [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]
Abstract

International audience; The challenge of this work was to investigate the role of topology in LCST hydrogels that strongly and reversibly thermo-reinforce their mechanical strength under isochoric conditions. To achieve this, two different hydrogels with opposite topologies were designed on the basis of grafted architectures using equal amounts of water-soluble chains (poly(N,N-dimethylacrylamide) = PDMA) and LCST polymer chains (poly(N-isopropylacrylamide) = PNIPA). By working under isochoric conditions, with almost 85 wt % of water in the whole temperature range (20–60 °C), we were able to clearly highlight the impact of the phase transition of PNIPA on the mechanical reinforcement of the gel without any interference of the volume transition. These graft hydrogels, designed with PNIPA in the backbone (GPN-D) or as pendant chains (GPD-N), have been studied more specifically by tensile tests and 2D neutron scattering at rest and under deformation. From these complementary techniques, we show that PNIPA side-chains in GPD-N self-assemble above their transition temperature into a micellar network greatly interfering with the covalent PDMA frame. While the elastic modulus increases reversibly more than ten times throughout the phase transition, other properties like elongation at break and fracture resistance are greatly enhanced with temperature. At high temperature and under extension, SANS data highlight the affine deformation of PNIPA domains. By comparison, the opposite topology with PNIPA forming the cross-linked backbone undergoes a similar phase separation with temperature and gives rise to a bicontinuous structure that aligns under loading. The collapsed phase being topologically defined as the load bearing phase, GPN-D displays remarkable fracture toughening with crack bifurcation at high temperature whereas GPD-N gels fracture in a more conventional way.

Published
2016
Full Text
View/download PDF

32. Recent developments and projects in SANS instrumentation at LLB-Orphée

Author

Annie Brûlet, Sylvain Desert, and Grégory Chaboussant

Subjects
Engineering, Spectrometer, Contrast variation, business.industry, General Physics and Astronomy, General Materials Science, Nanotechnology, Instrumentation (computer programming), Physical and Theoretical Chemistry, Neutron scattering, business, Engineering physics
Abstract

This article presents an overview of the recent developments in SANS and GISANS instrumentation at LLB-Orphee. SANS is a well-known technique, especially well adapted for research in material sciences, soft matter and nanosciences, which has proved to be particularly powerful to study complex systems, from nm to μm, taking full advantage of isotopic labelling and contrast variation methods. In this article, two instruments will be described in some details: TPA, the new VSANS (Very-Small Angle Neutron Scattering) instrument which is now fully functional and PA20, the new SANS spectrometer under construction, which will extend LLB’s capabilities in terms of SANS for magnetism with a polarized neutron option and Grazing Incidence SANS (GISANS).

Published
2012
Full Text
View/download PDF

33. Morphology study of a series of azobenzene-containing side-on liquid crystalline triblock copolymers

Author

Pierre-Antoine Albouy, Annie Brûlet, Xiaogong Wang, Patrick Keller, Min-Hui Li, and Wei Deng

Subjects
Materials science, Polymers and Plastics, Small-angle X-ray scattering, General Chemical Engineering, Organic Chemistry, Amorphous solid, chemistry.chemical_compound, Crystallography, Azobenzene, chemistry, Transmission electron microscopy, Liquid crystal, Phase (matter), Polymer chemistry, Copolymer, Lamellar structure
Abstract

A series of azobenzene containing side-on liquid crystalline ABA triblock copolymers were investigated. This triblock series possesses the same central liquid crystal block B and various lengths of the amorphous block A. Transmission electron microscopy (TEM), small angle X-rays and neutron scattering (SAXS and SANS) were used to study their morphologies. After annealing the samples over weeks at a temperature within the nematic temperature range of block B, different morphologies (disordered, lamellar, perforated layer and hexagonal cylinder) were observed by TEM. The alignment behavior of these azo triblock copolymers in the magnetic field for artificial muscle application, as well as the phase period and the order-disorder transition (ODT) were studied in situ by SANS.

Published
2012
Full Text
View/download PDF

34. Amphiphilic liquid-crystal block copolymer nanofibers via RAFT-mediated dispersion polymerization

Author

Xuewei Zhang, Chuong Bui, Bernadette Charleux, Annie Brûlet, Stéphanie Boissé, Jutta Rieger, Min-Hui Li, and Pierre-Antoine Albouy

Subjects
Dispersion polymerization, Materials science, Small-angle X-ray scattering, Chain transfer, General Chemistry, Condensed Matter Physics, Small-angle neutron scattering, chemistry.chemical_compound, chemistry, Nanofiber, Amphiphile, Polymer chemistry, Copolymer, Ethylene glycol
Abstract

Well-defined, cholesteryl-based, amphiphilic block copolymer nanofibers have been obtained in a simple, one-pot, ethanol/water dispersion polymerization process using poly((meth)acrylic acid-co-(poly(ethylene glycol) (meth)acrylate) copolymers end-functionalized by a reactive trithiocarbonate end-group as macromolecular reversible addition–fragmentation chain transfer agents (macroRAFT agents). The resulting highly concentrated dispersions were analyzed by TEM (transmission electron microscopy), cryo-TEM, SAXS (small angle X-ray scattering) and SANS (small angle neutron scattering), which allowed the shape and size of the nanoobjects formed in situ to be fully characterized and which revealed moreover the presence of a smectic order in the hydrophobic cores. Due to this particular substructure, the nanofiber organization was observed over a broad composition range of the amphiphilic block copolymers.

Published
2012
Full Text
View/download PDF

35. Thermoresponsive Amphiphilic Diblock Copolymers Synthesized by MADIX/RAFT: Properties in Aqueous Solutions and Use for the Preparation and Stabilization of Gold Nanoparticles

Author

Christophe Mingotaud, Mathias Destarac, Mariana Beija, Annie Brûlet, Jean-Daniel Marty, Stéphanie Sistach, and Virginie Rahal

Subjects
chemistry.chemical_classification, Materials science, Aqueous solution, General Chemical Engineering, Chain transfer, General Chemistry, Raft, Polymer, chemistry, Polymerization, Colloidal gold, Amphiphile, Polymer chemistry, Materials Chemistry, Copolymer
Abstract

Well-defined diblock copolymers comprising thermosensitive poly(N-isopropyl acrylamide) (PNIPAM) and poly(n-butylacrylate) (PBA) blocks were synthesized by macromolecular design by interchange of xanthates (MADIX)/reversible addition−fragmentation chain transfer polymerization (RAFT) using a xanthate-type mediating agent. Their behavior in aqueous solution as a function of temperature was studied by scattering and microscopy techniques. The cloud point temperature values were strongly correlated to the hydrophobic content of the copolymers. Moreover, above the cloud point, the block copolymer structure led to the formation of large reversible aggregates with well-defined sizes. Those polymers were then used to study the synthesis and stability of gold nanoparticles (AuNPs) dispersions either by coating preformed AuNPs or by in situ preparation. In this latter case, we showed that the appropriate choice of polymer concentration allows one to control the size of the AuNPs. Furthermore, the AuNPs were embedd...

Published
2010
Full Text
View/download PDF

36. pH and Temperature Responsive Polymeric Micelles and Polymersomes by Self-Assembly of Poly[2-(dimethylamino)ethyl methacrylate]-b-Poly(glutamic acid) Double Hydrophilic Block Copolymers

Author

Daniel Taton, Willy Agut, Christophe Schatz, Annie Brûlet, Sébastien Lecommandoux, Laboratoire de Chimie des Polymères Organiques (LCPO), Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Team 3 LCPO : Polymer Self-Assembly & Life Sciences, Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC), Team 1 LCPO : Polymerization Catalyses & Engineering, Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
CROSS-LINKING, Polymers, Glutamic Acid, 02 engineering and technology, 010402 general chemistry, Methacrylate, 01 natural sciences, Micelle, Lower critical solution temperature, GENE DELIVERY, Microscopy, Electron, Transmission, AQUEOUS-SOLUTIONS, Polymer chemistry, Electrochemistry, Copolymer, Nanotechnology, Scattering, Radiation, General Materials Science, POLY(2-VINYLPYRIDINIUM)-BLOCK-POLY(ETHYLENE OXIDE), DRUG-DELIVERY, Micelles, Spectroscopy, Aqueous solution, Chemistry, Temperature, POLYPEPTIDE DIBLOCK COPOLYMERS, COACERVATE CORE MICELLES, Surfaces and Interfaces, Hydrogen-Ion Concentration, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Nanostructures, 0104 chemical sciences, Nylons, [CHIM.POLY]Chemical Sciences/Polymers, Isoelectric point, NEUTRON-SCATTERING, Polymersome, Methacrylates, CLICK CHEMISTRY, Self-assembly, 0210 nano-technology, POLYION COMPLEX MICELLES
Abstract

International audience; The aqueous solution behavior of novel polypeptide-based double hydrophilic block copolymers (DHBCs), namely, poly[2-(dimethylamino)ethyl methacrylate]-b-poly(glutamic acid) (PDMAEMA-b-PGA), exhibiting pH- and temperature-responsiveness is presented using a combination of scattering techniques (light and neutron) and transmission electron microscopy. Close to the isoelectric point (IEP), direct or inverse electrostatic polymersomes are generated by electrostatic interactions developing between the two charged blocks and driving the formation of the hydrophobic membrane of the polymersomes, with the latter being stabilized in water by uncompensated charges. Under basic conditions, that is, when PDMAEMA is uncharged, the thermosensitivity of the DHBCs relates to the lower critical solution temperature (LCST) behavior of PDMAEMA around 40 degrees C. As a consequence, at pH = 11 and below this LCST, free chains of DHBC unimers are evidenced, while above the LCST the hydrophobicity of PDMAEMA drives the self-assembly of the DHBCs in a reversible manner. In this case, spherical polymeric micelles or polymersomes are obtained, depending on the PGA block length. These possibilities of variation in size and shape of morphologies that can be achieved as a function of temperature and/or pH variations open new routes in the development of multiresponsive nanocarriers for biomedical applications.

Published
2010
Full Text
View/download PDF

37. Ionic Liquid/Oil Microemulsions as Chemical Nanoreactors

Author

Florence Gayet, Pierre Lavedan, Jean-Daniel Marty, Nancy Lauth-de Viguerie, Chaker El Kalamouni, and Annie Brûlet

Subjects
chemistry.chemical_classification, Ternary numeral system, Chemistry, Analytical chemistry, Ionic bonding, Surfaces and Interfaces, Nanoreactor, Condensed Matter Physics, Toluene, chemistry.chemical_compound, Hydrocarbon, Chemical engineering, Ionic liquid, Electrochemistry, General Materials Science, Microemulsion, Imide, Spectroscopy
Abstract

The phase diagram and microstructure of the ternary system ionic, liquid benzylpyridinium bis(trifluoromethanesulfonyl)imide)/nonionic surfactant (octylphenol ethoxylate)/toluene, were studied by using conductivity measurements, dynamic light scattering, pulse field gradient spin-echo NMR, and small-angle neutron scattering. Three microregions were identified by conductivity measurements according to the percolation theory. The sizes of IL-in-oil microemulsions with various IL fractions were then determined by NMR and DLS and were found to be in accordance with the radii of gyration (approximately 2 or 3 nm) determined by SANS. The reverse IL-in-oil microemulsions were used as nanoreactors to perform a Matsuda-Heck reaction between p-methoxyphenyl diazonium salt and 2,3-dihydrofurane in the presence of a palladium catalyst. The reaction yields obtained were greater in microemulsions (67%) than in bulk IL (33%), highlighting a strong effect of confinement. Moreover, a direct correlation between the quantity of IL and the reaction yield was observed.

Published
2009
Full Text
View/download PDF

38. Radial collapse of carbon nanotubes for conductivity optimized polymer composites

Author

Raul Arenal, Alfonso San-Miguel, Silvana Botti, Tiago F. T. Cerqueira, Nicholas Blanchard, Christophe Adessi, Sylvie Le Floch, Miguel A. L. Marques, Annie Brûlet, Félix Balima, Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), University of Zaragoza - Universidad de Zaragoza [Zaragoza], Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Nanotube, Materials science, Carbon nanotube actuators, Mechanical properties of carbon nanotubes, 02 engineering and technology, General Chemistry, Carbon nanotube, Conductivity, 021001 nanoscience & nanotechnology, 01 natural sciences, Small-angle neutron scattering, law.invention, Optical properties of carbon nanotubes, Carbon nanotube metal matrix composites, Condensed Matter::Materials Science, law, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], General Materials Science, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], Composite material, 010306 general physics, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract

The optimization of the electronic conduction of carbon nanotube polymer composites is studied by tuning the radial geometry of the carbon nanotubes in a compression cycle. We have investigated the structural evolution of multi-walled carbon nanotubes in a polyamide matrix as a function of applied high pressure. Combining high resolution electron microscopy and small angle neutron scattering experiments, we conclude that the nanotube radial cross-section is irreversibly deformed following applied pressures up to 5 GPa. Studying highly percolated composites we observe that the sample resistivity drastically decreases with pressure up to about 2 GPa with no further change up to the maximum 5 GPa applied pressure. An important hysteresis is observed upon decompression which leads to an enhanced electrical conductivity of the composite in all the studied compression cycles with maximum pressures ranging from 1 to 5 GPa. Modelling the radial collapse of single-walled carbon nanotubes shows that the modified radial geometry can considerably improve the electronic transport properties in contacted carbon nanotube junctions. Our results open opportunities for engineering nanotube composites by controlling the radial collapse.

Published
2016
Full Text
View/download PDF

39. Thermoresponsive Micelles from Jeffamine-b-poly(<scp>l</scp>-glutamic acid) Double Hydrophilic Block Copolymers

Author

Sébastien Lecommandoux, Willy Agut, Annie Brûlet, Daniel Taton, Laboratoire de Chimie des polymères organiques (LCPO), Centre National de la Recherche Scientifique (CNRS)-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Université Sciences et Technologies - Bordeaux 1-Institut de Chimie du CNRS (INC), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Team 1 LCPO : Polymerization Catalyses & Engineering, Laboratoire de Chimie des Polymères Organiques (LCPO), Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC), Team 3 LCPO : Polymer Self-Assembly & Life Sciences, Université Sciences et Technologies - Bordeaux 1 (UB)-École Nationale Supérieure de Chimie et de Physique de Bordeaux (ENSCPB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
02 engineering and technology, 010402 general chemistry, 01 natural sciences, Lower critical solution temperature, Micelle, DELIVERY, chemistry.chemical_compound, Colloid, Dynamic light scattering, Polymer chemistry, Electrochemistry, Copolymer, SCATTERING, WATER, AQUEOUS-MEDIA, General Materials Science, Propylene oxide, DRUG, N-CARBOXYANHYDRIDES, Spectroscopy, SMALL-ANGLE NEUTRON, Ethylene oxide, Surfaces and Interfaces, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, POLYMERIZATION, DIBLOCK COPOLYMERS, [CHIM.POLY]Chemical Sciences/Polymers, chemistry, Polymerization, 0210 nano-technology
Abstract

National audience; Double hydrophilic block copolymers (DHBC) consisting of a Jeffamine block, a statistical copolymer based on ethylene oxide and propylene oxide units possessing a lower critical solution temperature (LCST) of 30 degrees C in water, and Poly(L-glutamic acid) as a pH-responsive block were synthesized by ring-opening polymerization of gamma-benzyl-L-glutamate N-carboxyanhydride using an amino-terminated Jeffamine macroinitiator, followed by hydrolysis. This DHBC proved thermoresponsive as evidenced by dynamic light scattering and small-angle neutron scattering experiments. Spherical micelles with a Jeffamine core and a poly(L-glutamic acid) corona were formed above the LCST of Jeffamine. The size. of the core of such micelles decreased with increasing temperature, with complete core dehydration being achieved at 66 degrees C. Such behavior, commonly observed for thermosensitive homopolymers forming mesoglobules, is thus demonstrated here for a DHBC that self-assembles to generate thermoresponsive micelles of high colloidal stability.

Published
2007
Full Text
View/download PDF

40. Improvement of data treatment in small-angle neutron scattering

Author

Didier Lairez, Alain Lapp, J. P. Cotton, and Annie Brûlet

Subjects
Physics, Normalization (statistics), Background subtraction, business.industry, Scattering, Detector, Neutron scattering, Small-angle neutron scattering, General Biochemistry, Genetics and Molecular Biology, Computational physics, Brillouin zone, Optics, business, Data reduction
Abstract

Small-angle neutron scattering has been successfully used since the 1970s. As a general rule, methods to extract the useful signal from that received by the detector are well known and give good results. At the Laboratoire Léon Brillouin, for example, these methods have been employed for a long time. However, the data reduction software has been changed for the following reasons. Problems are encountered if the container of the sample gives a spurious signal or if the scattering angle is so large that its cosine cannot be approximated by 1. In the present paper, generalizations of formulas are made in order to account for these difficulties. The decrease of scattered intensity delivered by an incoherent sample that is often observed at large angles is shown to be only due to a geometrical effect. The consequent modifications of the relations used for the normalization of cells of position-sensitive detectors and for the absolute calibration are given. As for the inherent background of the sample, the contribution of density fluctuations is usually neglected. This contribution is formally given as a function of the contrast lengths and of the isothermal compressibility of the sample. This new result allows numerical evaluations of the different terms of the inherent sample background. Practical examples are given. Finally, several methods, developed at the Laboratoire Léon Brillouin, are given to determine the background properly. They are based on systematic measurements of transmissions and background levels of suitably prepared blank samples.

Published
2007
Full Text
View/download PDF

41. The role of solvent swelling in the self-assembly of squalene based nanomedicines

Author

Patrick Couvreur, Aurel Radulescu, Fatima Zouhiri, Annie Brûlet, Didier Desmaële, Isabelle Grillo, Olivier Spalla, Debasish Saha, Fabienne Testard, Sylvain Desert, Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire (LIONS), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), Institut Galien Paris-Sud (IGPS), Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), ILL, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Jülich Centre for Neutron Science (JCNS), Forschungszentrum Jülich GmbH | Centre de recherche de Juliers, Helmholtz-Gemeinschaft = Helmholtz Association-Helmholtz-Gemeinschaft = Helmholtz Association, and Palacin, Serge

Subjects
Squalene, Nanoparticle, Antineoplastic Agents, chemistry.chemical_compound, Scattering, Small Angle, medicine, Organic chemistry, Particle Size, ComputingMilieux_MISCELLANEOUS, Coalescence (physics), [CHIM.MATE] Chemical Sciences/Material chemistry, Ethanol, Water, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, Condensed Matter Physics, Small-angle neutron scattering, Solvent, Neutron Diffraction, Nanomedicine, chemistry, Chemical engineering, Solvents, Nanoparticles, Particle size, Swelling, medicine.symptom
Abstract

International audience; Squalene based nanoparticles obtained via nanoprecipitation are promising candidates as efficient anti-cancer drugs. In order to highlight their preparation process and to facilitate further clinical translation, the present study enlightens the paramount role of the solvent in the formation of these nanomedicines. Three different squalene-based nanoparticles, i.e. squalenic acid, deoxycytidine squalene and gemcitabine squalene, have been investigated before and after organic solvent evaporation. Size and structural analysis by Small Angle Neutron Scattering revealed that droplets' size was uniquely controlled by the solvent composition (ethanol–water), which evolved during their gradual formation. The particles were preferably swollen by water and the swelling increased when less ethanol was present. Either coalescence or fragmentation was observed depending on the increase or decrease of the ethanol content, supporting an equilibrium control of the size. Moreover, a high water swelling was observed for the three local organization of the nanodroplets (hexagonal for gemcitabine squalene, cubic for deoxycytidine and not structured for squalenic acid) and could be the source of the previously reported efficiency of related anti-cancer squalene based nanomedicines.

Published
2015
Full Text
View/download PDF

42. Influence of topology of LCST-based graft copolymers on responsive assembling in aqueous media

Author

Nicolas Sanson, Annie Brûlet, Dominique Hourdet, Hui Guo, Alba Marcellan, Pattuparambil R. Rajamohanan, Sciences et Ingénierie de la Matière Molle (SIMM), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Central NMR Facility, National Chemistry Laboratory, Université Pierre et Marie Curie - Paris 6 (UPMC)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
chemistry.chemical_classification, Phase transition, Materials science, Polymers and Plastics, Aqueous medium, Transition temperature, Organic Chemistry, 02 engineering and technology, Polymer, 010402 general chemistry, 021001 nanoscience & nanotechnology, Topology, 01 natural sciences, Lower critical solution temperature, Small-angle neutron scattering, 0104 chemical sciences, [CHIM.POLY]Chemical Sciences/Polymers, chemistry, Materials Chemistry, Copolymer, 0210 nano-technology, Topology (chemistry)
Abstract

International audience; This work, based on structure/properties relationships of associating polymers, aims to investigate the role of topology in the self-assembling behavior of responsive graft copolymers. For that purpose, two graft copolymers with inverse topologies were prepared with similar amounts of water-soluble chains (poly(N,N-dimethylacrylamide) = PDMA) and LCST polymer chains (poly(N-isopropylacrylamide) = PNIPA). In pure water, and above 3 wt%, PNIPA-g-PDMA and PDMA-g-PNIPA exhibit very similar macroscopic properties with a sol/gel transition above 35 °C related to the microphase separation of PNIPA sequences. From complementary experiments, performed by DSC, 1H NMR and small angle neutron scattering, we show that the phase transition of PNIPA is more abrupt when NIPA units are located within the backbone, compared to side-chains. Nevertheless, well above their transition temperature, the two copolymers display very similar bicontinuous structures where PNIPA sequences self aggregate into concentrated percolating domains (about 70 wt% at 60 °C) characterized by a frozen dynamics. On the other hand, when salt or surfactant molecules are added into unentangled semi-dilute aqueous solution, the PNIPA-g-PDMA sample does not percolate anymore above the transition temperature while PDMA-g-PNIPA still demonstrate thermothickening properties that are correlated to the ability of water-soluble PDMA chains to bridge PNIPA aggregates.

Published
2015
Full Text
View/download PDF

43. Thermoreversible Behavior of Associating Polymer Solutions: Thermothinning versus Thermothickening

Author

and Annie Brûlet, Klára Podhájecká, Dominique Hourdet, Jayant Gadgil, Prakash P. Wadgaonkar, and Manohar V. Badiger

Subjects
chemistry.chemical_classification, Aqueous solution, Polymers and Plastics, Scattering, Organic Chemistry, Thermodynamics, Polymer, Neutron scattering, Lower critical solution temperature, Inorganic Chemistry, Hydrophobic effect, chemistry, Volume fraction, Polymer chemistry, Materials Chemistry, Side chain
Abstract

Self-assembling properties of poly(sodium acrylate) grafted with dodecyl [C12], PAAgC12, or poly(N-isopropylacrylamide) [PNIPA] side chains, PAAgPNIPA, were studied in unentangled semidilute aqueous solution. While PAAgC12 self-associates through hydrophobic interactions, the gelation of PAAgPNIPA is triggered by heating in response to the lower critical solution temperature of PNIPA (LCST ∼ 32 °C). The local structure of the physical networks was investigated by small-angle neutron scattering, and the scattering patterns were described using a polydisperse sphere model taking into account hard-sphere interactions. This model allow us to draw a realistic picture of physical gels with quantitative information concerning the size of hydrophobic cores, the volume fraction of stickers in the aggregates, the fraction of stickers which take part in the aggregation process, the range of repulsive interactions, and the structural modifications induced by temperature. The description of the network is in good agre...

Published
2005
Full Text
View/download PDF

44. Small-angle neutron-scattering study of the microphase separation in the Pr0.66Ca0.33MnO3 manganite

Author

N Guiblin, Vincent Hardy, Silvana Mercone, Damien Saurel, Ch. Simon, Annie Brûlet, and C. Martin

Subjects
Crystal, Nuclear magnetic resonance, Materials science, Magnetic domain, Condensed matter physics, Ferromagnetism, Crystal structure, Texture (crystalline), Electrical and Electronic Engineering, Condensed Matter Physics, Manganite, Small-angle neutron scattering, Electronic, Optical and Magnetic Materials
Abstract

We report a SANS study of the microphase separation texture of a Pr 0.66 Ca 0.33 MnO 3 crystal as a function of temperature. At T C , ferromagnetic domains display elongated shapes randomly oriented with respect to the crystalline structure, which transform, at lower temperatures, in a texture of randomly oriented and polydisperse 2D sheets of 2 nm average thickness.

Published
2004
Full Text
View/download PDF

45. Jean-Pierre Cotton (1941–2016)

Author

Mohamed Daoud, Annie Brûlet, and Bernard Farnoux

Subjects
Physics, Nuclear and High Energy Physics, Astrophysics, Soft matter, Small-angle neutron scattering, Atomic and Molecular Physics, and Optics
Abstract

Jean-Pierre Cotton passed away on January 20, 2016, at the age of 74. He was a leading figure in soft matter studies by Small Angle Neutron Scattering (SANS). As we will see below, he took advantag...

Published
2016
Full Text
View/download PDF

46. De-mixing dynamics of a binary liquid system in a controlled-pore glass

Author

Sebastian Schemmel, Thomas Hellweg, Annie Brûlet, Gernot Rother, H Eckerlebe, and Gerhard H. Findenegg

Subjects
Heavy water, Materials science, Scattering, Biophysics, Analytical chemistry, Surfaces and Interfaces, General Chemistry, Atmospheric temperature range, Mesoporous silica, chemistry.chemical_compound, Nuclear magnetic resonance, chemistry, General Materials Science, Neutron, Soft matter, Spectroscopy, Order of magnitude, Biotechnology
Abstract

The temperature-induced microphase separation of the binary liquid system iso-butyric acid+heavy water (iBA + D2O) in a mesoporous silica glass (CPG-10-75) of nominal pore width 7.5 nm was investigated by neutron spin-echo spectroscopy (NSE) and neutron small-angle scattering (SANS). Two mixtures of different composition were studied at different scattering angles at temperatures above and below the bulk phase transition temperature. The phase separation in the pore space is found to occur at a lower temperature than the bulk transition and extends over a significant temperature range. The effective diffusion coefficient derived from NSE at low scattering angles is found to decrease by one order of magnitude from 70 C-circle to 20 C-circle. This observation is attributed to the growing size of concentration fluctuations having a cut-off at ca. 8 nm, which corresponds to the mean pore size. The dynamics of the concentration fluctuations appears to be strongly influenced by the confinement in the pores, as it differs strongly from the bulk behaviour. These results are consistent with the preliminary results of the SANS study.

Published
2003
Full Text
View/download PDF

47. Structural Evolution of a Stimulus-Responsive Diblock Polypeptide Micelle by Temperature Tunable Compaction of its Core

Author

Ashutosh Chilkoti, Olivier Sandre, Laure Bataille, Annie Brûlet, Sarah R. MacEwan, Sébastien Lecommandoux, Elisabeth Garanger, Laboratoire de Chimie des Polymères Organiques (LCPO), Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC), Imagerie Moléculaire et Nanobiotechnologies - Institut Européen de Chimie et Biologie (IECB), Université Sciences et Technologies - Bordeaux 1-Centre National de la Recherche Scientifique (CNRS), Team 3 LCPO : Polymer Self-Assembly & Life Sciences, Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC), Duke Univ, Dept Biomed Engn, Duke University [Durham], Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Centre National de la Recherche Scientifique (CNRS), Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
DYNAMICS, Materials science, Polymers and Plastics, Thermodynamic equilibrium, Dispersity, Multiangle light scattering, 02 engineering and technology, Neutron scattering, 010402 general chemistry, 01 natural sciences, Micelle, Inorganic Chemistry, Polymer chemistry, AQUEOUS-SOLUTIONS, Materials Chemistry, Copolymer, WATER, POLY(ETHYLENE OXIDE), RECURSIVE DIRECTIONAL LIGATION, chemistry.chemical_classification, HYDROPHOBIC HYDRATION, PROTEIN-BASED POLYMERS, Organic Chemistry, Polymer, 021001 nanoscience & nanotechnology, 0104 chemical sciences, BLOCK-COPOLYMERS, MOLECULAR-WEIGHT, [CHIM.POLY]Chemical Sciences/Polymers, chemistry, Chemical physics, Radius of gyration, 0210 nano-technology, TRANSITION
Abstract

International audience; With a perfectly defined primary structure, both in terms of monomer sequence and chain length, recombinant polypeptides obtained by protein engineering techniques allow the investigation of structure property relationships at a level of detail that is difficult to achieve with traditional synthetic polymers because of the precision with which their sequence can be defined. In the present work, we have studied the behavior and temperature-triggered self-assembly of a series of diblock recombinant elastin-like polypeptides (ELPs) with the goal of elucidating the mechanism of their self-assembly into micelles. Aqueous solutions of diblock ELPs were studied below and above their critical micellar temperature (CMT) by multiangle light scattering and small-angle neutron scattering techniques. Below the CMT, the radius of gyration of soluble ELP chains follows a power law as a function of molecular weight with an exponent value close to 0.5 that is characteristic of Gaussian coil conformations. As the temperature reaches the CMT, attractive interactions between the more hydrophobic block of diblock ELP chains leads to the self-assembly of monodisperse spherical micelles at thermodynamic equilibrium. Above the CMT, micelles expel water molecules from their core whose densification is evidenced by the monotonic increase in the light and neutron scattering intensities as a function of temperature. The behaviors of these different diblock ELPs in solution and as self-assembled nanoparticles above the CMT following universal experimental scaling laws make them analogous to synthetic amphiphilic diblock copolymers (star-like vs crew-cut micelle models). These studies also shed light on the important role of water in the thermal behavior of these thermally responsive self-assembling diblock polypeptides and suggest a new design parameter thermally triggered desolvation and densification of the core of micelles that can be fine-tuned at the sequence level to control the density of self-assembled polymer nanoparticles.

Published
2015
Full Text
View/download PDF

48. Phase Separation and Nanodomain Formation in Hybrid Polymer/Lipid Vesicles

Author

Marc Schmutz, Olivier Sandre, Thi Phuong Tuyen Dao, Mériem Er-Rafik, Fábio Fernandes, Romain Salva, Jean-François Le Meins, Manuel Prieto, Annie Brûlet, Laboratoire de Chimie des Polymères Organiques (LCPO), Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC), Universidade de Lisboa (ULISBOA), Team 3 LCPO : Polymer Self-Assembly & Life Sciences, Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Université de Bordeaux (UB)-Institut de Chimie du CNRS (INC), Institut Charles Sadron (ICS), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, ANR-12-BS08-0018,KBT,Cinétique de Translocation de Particules à travers de Bicouches Auto-Assemblées(2012), Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Universidade de Lisboa = University of Lisbon (ULISBOA), Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Ecole Nationale Supérieure de Chimie, de Biologie et de Physique (ENSCBP)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
NANODOMAINS, Materials science, Polymers and Plastics, LIPID MEMBRANES, 7. Clean energy, Micelle, Inorganic Chemistry, Hydrophobic mismatch, Materials Chemistry, Lipid bilayer phase behavior, Lipid bilayer, RAFTS, Fluorescence resonance energy transfer FRET, chemistry.chemical_classification, MICELLES, Vesicle, Organic Chemistry, Hybrid membranes, Polymer, Small-angle neutron scattering, LIPID-POLYMER BLENDS, Crystallography, Förster resonance energy transfer, [CHIM.POLY]Chemical Sciences/Polymers, chemistry, LINE TENSION, Biophysics, lipids (amino acids, peptides, and proteins), MEMBRANE COMPOSITION, [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]
Abstract

International audience; Hybrid polymer/lipid large unilamellar vesicles (LUVS) were studied by small angle neutron scattering (SANS), time-resolved Forster resonance energy transfer (TR-FRET), and cryo-transmission electron microscopy (cryo-TEM). For the first time in hybrid vesicles, evidence for phase separation at the nanoscale was obtained, leading to the formation of stable nanodomains enriched either in lipid or polymer. This stability was allowed by using vesicle-forming copolymer with a membrane thickness dose to the lipid bilayer thickness, thereby minimizing the hydrophobic mismatch at the domain periphery. Hybrid giant unilamellar vesicles (GUVs) with the same composition have been previously shown to be unstable and susceptible to fission, suggesting a role of curvature in the stabilization of nanodomains in these structures.

Published
2015
Full Text
View/download PDF

49. Effect of Dense Grafting on the Backbone Conformation of Bottlebrush Polymers: Determination of the Persistence Length in Solution

Author

Michèle Schappacher, Frédéric Chécot, J. P. Cotton, Annie Brûlet, Redouane Borsali, and Alain Deffieux, and Sébastien Lecommandoux

Subjects
chemistry.chemical_classification, Persistence length, Materials science, Polymers and Plastics, Scattering, Organic Chemistry, Polymer, Neutron scattering, Polymer brush, Grafting, Inorganic Chemistry, Crystallography, chemistry.chemical_compound, chemistry, Polymer chemistry, Materials Chemistry, Copolymer, Polystyrene
Abstract

The effect of dense grafting on the polymer brush's conformation is studied by small-angle neutron scattering on well-defined branched copolymers. We have determined the persistence length lp of the backbone of poly(chlorovinyl ether) grafted with polystyrene (PCEVE-g-PS) copolymers. In a good solvent, this length lp can be directly obtained from the scattering vector q* at which the polymer chain locally behaves as a rod; i.e., its form factor enters the q-1 variation regime. This method is first applied to a linear PCEVE polymer, as reference. Then, we compare to the branched copolymers by using the matching condition for the PS branches in order to only measure the form factor of the PCEVE backbone. From the flexible linear chain to the bottlebrush-like polymer, the persistence length increases from 12 to 110 A.

Published
2002
Full Text
View/download PDF

50. Shear effects on expanded graphite under uniaxial pressure: An in situ small angle neutron scattering study

Author

Laurent Duclaux, Alfonso San-Miguel, Vittoria Pischedda, Annie Brûlet, Félix Balima, Sylvie Le Floch, Peter Lindner, Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut Laue-Langevin (ILL), ILL, Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Laboratoire de Chimie Moléculaire et Environnement (LCME), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, [SDE.IE]Environmental Sciences/Environmental Engineering, Mineralogy, General Chemistry, Neutron scattering, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, Small-angle neutron scattering, Fractal dimension, Shear (geology), [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Shear stress, General Materials Science, Graphite, Composite material, Porosity, Anisotropy
Abstract

International audience; In a previous work [1] we elucidated the in situ evolution of the porosity of out-of-plane com- pressed flexible graphite under uniaxial pressure up to 1000 bar using small-angle neutron scattering (SANS) technique. In order to understand the influence of shear effect on the properties of flexible graphite we study, in the present paper, the in situ behaviour of in-plane compressed flexible graphite under a uniaxial pressure. The sample had a pleated layered structure in which anisotropic SANS patterns revealed a distribution of differently oriented ellipsoid pores. Uniaxial compression generates important shear effects in this kind of sample.We have determined the evolution of the system fractal dimension, pore size distribu- tion and apparent specific surface area with applied pressure which together allow us to describe the meso and macro pore structure evolution. Under pressure, the irreversible col- lapse and splitting of larger pores into smaller size ones which is characteristic of out-of- plane uniaxial compression [1], is accompanied, in the presence of shear stress compo- nents, by an in-plane slipping mechanism giving rise to cracks and consequently to inter- face formation.

Published
2014
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results