Search

Thrombus formation and infections caused by bacterial adhesion are the most common causes of failure in blood-contacting medical devices. Reducing interaction of pathogens by using repellent surfaces has proven to be a successful strategy in preventing device failure. However, designing scale-up methodologies to create large scale repellent surfaces remains challenging. To address this need, we have created an all-polymeric lubricant-infused system using an industrially viable swelling-coagulation solvent (S-C) method. This induces hierarchically structured micro/nano features onto the surface, enabling improved lubricant-infusion. Poly(3,3,3 - trifluoropropylmethylsiloxane) (PTFS) was used as the lubricant of choice, a previously unexplored omniphobic non-volatile silicone oil. This resulted in all-polymeric liquid-infused surfaces that are transparent and flexible with long-term stability. Repellent properties have been demonstrated using human whole blood and methicillin-resistant Staphyloccus aureus (MRSA) bacteria matrices, with lubricated surfaces showing 93% reduction in blood stains and 96.7% reduction in bacterial adherence. The developed material has the potential to prevent blood and pathogenic contamination for a range of biomedical devices within healthcare settings.

It is possible to prepare elastic and thermoreversible gel electrolytes with significant electroactivity by dissolving minimal weight fractions of ultra-high molecular weight polyethylene oxide (UHMW PEO) in an aluminum deep eutectic solvent (DES) electrolyte composed of AlCl and urea at a molar ratio of 1.5 : 1 (AlCl/urea). The experimental vibrational spectra (FTIR and Raman) provide valuable information on the structure and composition of the gel electrolyte. However, the complexity of this system requires computational simulations to help interpretation of the experimental results. This combined approach allows us to elucidate the speciation of the DES liquid electrolyte in the gel and how it interacts with the polymer chains to give rise to an elastic network that retains the electroactivity of the liquid electrolyte to a very great extent. The observed reactions occur between the ether in the polymer and both the amine groups in urea and the aluminum species. Thus, similar elastomeric gels may likely be prepared with other aluminum liquid electrolytes, making this procedure an effective way to produce families of gel aluminum electrolytes with tunable rheology and electroactivity., This work was financed by SALBAGE project funded by the European Union under the H2020-FETOPEN-1-2016-2017 call (GA n° 766581). The authors are very grateful to Dr. Gary Ellis for making the recording of the Raman spectra possible, and to the researchers in the SALBAGE consortium, especially Dr. Ana López- Cudero for fruitful discussions

In this work, Polyethylene terephthalate (PET), one of the most widely consumed polymers, has been used as starting material for the development of non-stick surfaces through a fast, simple and scalable method based on solvent-induced crystallization to generate roughness, followed by a fluorination step. Several solvents were tested, among which dichloromethane was chosen because it gives rise to the formation of a particulate layer with rough topography. This particulate layer was covered by a polymer thin and smooth skin that must be removed to leave the rough layer as surface. The skin has been successfully removed by two strategies based on mechanical and chemical removal, each strategy producing different surface properties. A final treatment with a diluted solution of a fluorinated silane showed that it is possible to obtain PET surfaces with a water contact angle higher than 150 and low water adhesion. The reason behind this behavior is the development of a hierarchical rough profile during the induced polymer crystallization process. These surfaces were characterized by XRD, FTIR and DSC to monitor solvent induced crystallization. Topography was studied by SEM and optical profilometry. Wetting behavior was studied by measuring the contact angles and hysteresis., This research was funded by the Spanish Ministry of Science and Innovation and Universities MAT2016-81001-P and PID2019-109401 GB-I00

Physical gels made of poly(ethylene oxide) (PEO) and deep eutectic solvents urea-Li bis(trifluoromethanesulfonyl)imide (TFSI) and ethylene glycol/LiTFSI, or pyrrolidinium ionic liquid solutions PYR13TFSI-LiTFSI and PYR14TFSI-LiTFSI, are prepared by a fast, single-step process, which involves no auxiliary solvents or intermediates and is reproducible and scalable. The properties of these gels are studied as a function of the PEO content and its molecular weight and the nature of the liquid electrolyte. The gels prepared with a low concentration (1-5 wt %) of ultrahigh molecular weight (UHMW) PEO are tough, stretchable materials which resemble soft elastomers and are also self-healing and transparent. Their rheology shows the conventional behavior of physical polymer gels, so that the higher the molecular weight of PEO, the lower the polymer concentration needed to produce the gel. However, the ion conductivities and diffusivities of the gels are striking, in many cases being equal to or significantly higher than those of pure liquid electrolytes. This ion conductivity enhancement is the highest for the lowest PEO concentration with the highest molecular weight. This unprecedented molecular weight dependence of conductivity and diffusivity is the result of two combined effects: the liquid electrolyte chemical structure modification as a consequence of the addition of PEO and the development of elastic networks, where ion mobility and rheology are uncoupled when the PEO added is of UHMW., We are grateful to the Characterization Service of ICTP-CSIC for the PGSE NMR measurements included in this work and to Ana López-Cudero for fruitful discussions and revision of the final manuscript. Funding by EU projects SALBAGE H2020-FETOPEN-1-2016-27 G.A 766581 and AMAPOLA H2020-EIC-FETPROACT-2019 G.A. 951902 is gratefully acknowledged.

Thrombus formation and infections caused by bacterial adhesion are the most common causes of failure in blood-contacting medical devices. Reducing the interaction of pathogens using repellent surfaces has proven to be a successful strategy in preventing device failure. However, designing scale-up methodologies to create large-scale repellent surfaces remains challenging. To address this need, we have created an all-polymeric lubricant-infused system using an industrially viable swelling-coagulation solvent (S-C) method. This induces hierarchically structured micro/nano features onto the surface, enabling improved lubricant infusion. Poly(3,3,3-trifluoropropylmethylsiloxane) (PTFS) was used as the lubricant of choice, a previously unexplored omniphobic nonvolatile silicone oil. This resulted in all-polymeric liquid-infused surfaces that are transparent and flexible with long-term stability. Repellent properties have been demonstrated using human whole blood and methicillin-resistant Staphylococcus aureus (MRSA) bacteria matrices, with lubricated surfaces showing 93% reduction in blood stains and 96.7% reduction in bacterial adherence. The developed material has the potential to prevent blood and pathogenic contamination for a range biomedical devices within healthcare settings., E.A. thanks Spanish Ministry of Science and Innovation for the FPI Grant (BES-2017-080057). T.F.D. acknowledges support from NSERC Discovery Grant, Ontario Early Researcher Award and McMaster Start-up funds to T.F.D. T.F.D and Z.H.D are Tier II Canada Research Chairs.

Superhydrophobicity has proven to be a useful tool to meet the needs of the new circular economy, even though its large-scale development continues to be challenging mainly due to the low affordability of micro and nanometric roughness generation methods. In this work, non-stick polymer materials based on Poly(vinylidene Fluoride), PVDF, and its blends with Poly(methyl methacrylate), PMMA, were developed by a simple, fast and industrially accessible solvent-induced method aligned with the ecodesign philosophy. The chemical and structural features that determine the wetting behavior are evaluated in 18 different surfaces, that present varied surface energy (blend composition from 100 to 60:40 PVDF:PMMA) and topography (controlled by the method conditions). Wetting behavior was analyzed by measuring the water contact angles and its hysteresis, whereas the roughness parameters were determined by optical profilometry. By tuning the blend composition and the solvent-induced process conditions, it was possible to obtain either superhydrophobic surfaces with contact angles higher than 160° and hysteresis lower than 5° or parahydrophobic surfaces with high contact angles and high water adhesion. The fundamental features of both wetting behaviors were critically discussed. In addition, a proof of concept of the industrial viability of the method on a fragment of a commercial piece made of PVDF was successfully carried out., The authors would like to acknowledge the Spanish Ministry for funding (PID2019-109401GB-I00). E.A. thanks to Spanish Ministry for the FPI Grant (BES-2017-080057).

Gel electrolytes are prepared with Ultra High Molecular Weight (UHMW) polyethylene oxide (PEO) in a concentration ranging from 5 to 30 wt.% and Li- and Na-doped 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide (PYR14-TFSI) by a simple procedure consisting of dissolving PEO by melting it directly in the liquid electrolyte while stirring the blend. This procedure is fast, reproducible and needs no auxiliary solvents, which makes it sustainable and potentially easy to scale up for mass production. The viability of the up-scaling by extrusion has been studied. Extrusion has been chosen because it is a processing method commonly employed in the plastics industry. The structure and morphology of the gel electrolytes prepared by both methods have been studied by DSC and FTIR, showing small differences among the two methods. Composite gels incorporation high concentrations of surface modified sepiolite fibers have been successfully prepared by extrusion. The rheological behavior and ionic conductivity of the gels have been characterized, and very similar performance of the extruded and manually mixed gels is detected. Ionic conductivity of all the gels, including the composites, are at or over 0.4 mS cm−1 at 25 °C, being at the same time thermoreversible and self-healing gels, tough, sticky, transparent and stretchable. This combination of properties, together with the viability of their industrial up-scaling, makes these gel electrolyte families very attractive for their application in energy storage devices., Spanish Ministry of Science and Innovation is gratefully acknowledged for funding through the project PID2019-109401GB-I00.

This work deals with the search of polymers apt for the preparation of solid-like chloroaluminate-based electrolytes. To accomplish this, the solubility and gelling ability of a large set of polymers in the deep eutectic solvent AlCl3:urea (uralumina) are studied, followed by the characterization of the electrochemical activity of the gels. The polymers are directly dissolved in urea:AlCl3 without auxiliary solvents following a fast and scalable gel preparation methodology previously reported for ultra-high molecular weight (UHMW) polyethylene oxide (PEO). The list of polymers studied includes diverse chemical structures, different thermal properties and different aggregation states at the mixing temperature of 70 ◦C, defined by the thermal stability of AlCl3:urea. To avoid a molecular weight influence on the ionogel rheological properties, polymers with molecular weight close to 100,000 g mol 1 have been chosen. The polymers considered include poly(ε-caprolactone) (PCL), poly (dimethyl siloxane) (PDMS), poly(vinyl pyrrolidone) (PVP), polyformal, thermoplastic polyurethanes, polymethacrylates, polyacetates and the elastomer SEBS. It was found that together with polyethylene oxide, only poly(ε-caprolactone) and poly(dimethyl siloxane) are soluble and produce gel electrolytes with AlCl3:urea. The solubility rules of polymers in chloroaluminates are discussed. The stripping/plating of Al and the ionic conductivity of PEO, PDMS and PCL ionogels are studied by cyclic voltammetry and impedance spectroscopy. PDMS proves to be as efficient as PEO to produce ionogels at low polymer concentration, that are also self-standing and electroactive, whereas a higher concentration of PCL is required to produce self-standing gels. The molecular structure of the ionogels and the modification of the chloroaluminate speciation is studied by vibrational spectroscopies, and supported by DFT calculations., The authors acknowledge financial support from project European Union H2020-FETOPEN-1-2016-2017 call (G A. No. 766581, SALBAGE project). All calculations were carried out at the Wrocław Center for Networking and Supercomputing, Grant 346.

Polymer gel electrolytes (PGEs) have been prepared with copolymers based on imida zolium ionic liquids and the deep eutectic mixture of AlCl3 :urea (uralumina) as liquid electrolyte. The copolymers were synthesized by photopolymerization of vinylpirrolidone or methylmethacrylate with imidazolium bis (trifluoromethane sulfonyl) imide (TFSI) ionic liquid monomer and mixed in an increasing range of wt.% with uralumina. The rheology and electrochemical activity of PGEs were highly dependent on the molar ratio of charged groups and copolymer content. Structure of the PGEs was studied by FTIR and Raman spectroscopy and a correlation between interactions poly mer/uralumina and changes in speciation of uralumina was established. Despite the low molecular weight of the copolymers, the resulting polymer electrolytes develop elastomeric character associated with the binding ionic species. Although there is room to improve the electrochemical activity, in this study these new gels provide sufficient electroactivity to make them feasible alternatives as electrolytes in secondary aluminum batteries., This research was financed by Project European Union H2020-FETOPEN-1-2016-2017 call (G.A. No. 766581, SALBAGE project).

Polymer gel electrolytes (PGEs) have been prepared with copolymers based on imidazolium ionic liquids and the deep eutectic mixture of AlCl3:urea (uralumina) as liquid electrolyte. The copolymers were synthesized by photopolymerization of vinylpirrolidone or methylmethacrylate with imidazolium bis (trifluoromethane sulfonyl) imide (TFSI) ionic liquid monomer and mixed in an increasing range of wt.% with uralumina. The rheology and electrochemical activity of PGEs were highly dependent on the molar ratio of charged groups and copolymer content. Structure of the PGEs was studied by FTIR and Raman spectroscopy and a correlation between interactions polymer/uralumina and changes in speciation of uralumina was established. Despite the low molecular weight of the copolymers, the resulting polymer electrolytes develop elastomeric character associated with the binding ionic species. Although there is room to improve the electrochemical activity, in this study these new gels provide sufficient electroactivity to make them feasible alternatives as electrolytes in secondary aluminum batteries.

It is possible to prepare elastic and thermoreversible gel electrolytes with significant electroactivity by dissolving minimal weight fractions of ultra-high molecular weight polyethylene oxide (UHMW PEO) in an aluminum deep eutectic solvent (DES) electrolyte composed of AlCl

The development of novel solid electrolytes, which can be processed using solvent-free methods, is one of the keys for successful industrialization of solid state batteries and their further implementation in electrical vehicles. Here, we study thermoplastic solid state electrolytes based on polyethylene oxide (PEO), 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYRTFSI), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and two inorganic fillers with different morphology and nature (modified sepiolite (TPGS-S) and garnet-type LiLaZrNbO (LLZNO) prepared by solvent free extrusion method. Several thermoplastic polymer electrolytes (TPEs) are prepared and comprehensively studied. Composite thermoplastic electrolyte TPE-S10G10 containing 10 wt% of TPGS-S and 10 wt% of LLZNO fillers shows the best electrochemical performance in Li-LiFePO solid state batteries operating under 0.2C/0.5D cycling conditions at 60 &Deg;C. Solid state cell with TPE-S10G10 electrolyte retains 80% of initial discharge capacity after 540 cycles. Thus, a synergetic effect of using two different fillers, which can be exploited during the development of TPEs, is clearly demonstrated., This study was supported by the Comunidad de Madrid (Project Ref. LIQUORGAS-CM, S2013/MAE-2800). Francisco González is grateful to CONACYT-SENER for the scholarship granted (CVU559770/Registro297710).

Composite materials of conjugated polymers/cellulose were fabricated by incorporating different polythiophene-derivative polymers: Poly(3,4-ethylenedioxythiophene) (PEDOT) and an alkylated derivative of poly(3,4-propylenedioxythiophene) (PProDOT). These conjugated polythiophenes were deposited by casting or spray coating methodologies onto three different cellulose substrates: Conventional filters papers as cellulose acetate, cellulose grade 40 Whatman® and cellulose membranes prepared from cellulose microfibers. The preparation of composite materials was carried out by two methodologies: (i) by employing in-situ polymerization of 3,4-ethylenedioxithiophene (EDOT) or (ii) by depositing solutions of poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) or lab-synthetized PProDOT. Composite materials were studied in terms of electrical conductivity and surface morphology assessed by impedance spectroscopy, surface conductivity, SEM, and 3D optical profilometry. In-situ composite materials prepared by spray coating using iron trifluoromethane sulfonate as oxidizing agent can be handled and folded as the original cellulose membranes displaying a surface conductivity around 1 S∙cm−1. This versatile procedure to prepare conductive composite materials has the potential to be implemented in flexible electrodes for energy storage applications., This research was supported by CDTI research project IDI- 20180087. We also thanks the Consejo Nacional de Ciencia y Tecnología for CVU 559770/Registro 297710 and S2013/MAE-2800.

Solid electrolytes for Li transport have been prepared by melt-compounding in one single step. Electrolytes are composed of polyvinylidene fluoride&ndash, hexafluoropropylene (PVDF&ndash, HFP) with PYR13TFSI on its own or with varying concentration of LiTFSI. While the extrusion of PVDF&ndash, HFP with PYR13TFSI is possible up to relatively high liquid fractions, the compatibility of PVDF&ndash, HFP with LiTFSI/PYR13TFSI solutions is much lower. An organo-modified sepiolite with D-&alpha, tocopherol polyethylene glycol 1000 succinate (TPGS-S) can be used to enhance the compatibility of these blends and allows to prepare homogeneous PYR13TFSI/LiTFSI/PVDF&ndash, HFP electrolytes with controlled microphase separations by melt-compounding. The structure and morphology of the electrolytes has been studied by FTIR, differential scanning calorimetry (DSC), SEM, and AFM. Their mechanical properties have been studied by classical strain&ndash, stress experiments. Finally, ionic conductivity has been studied in the &minus, 50 to 90 &deg, C temperature range and in diffusivity at 25 &deg, C by PFG-NMR. These electrolytes prove to have a microphase-separated morphology and ionic conductivity which depends mainly on their composition, and a mechanical behavior typical of common thermoplastic polymers, which makes them very easy to handle. Then, in this solvent-free and scalable fashion, it is possible to prepare electrolytes like those prepared by solvent casting, but in few minutes instead of several hours or days, without solvent evaporation steps, and with ionic conductivities, which are very similar for the same compositions, above 0.1 mS&middot, cm&minus, 1 at 25 &deg, C. In addition, some of the electrolytes have been prepared with high concentration of Li ion, what has allowed the anion exchange Li transport mechanism to contribute significantly to the overall Li diffusivity, making DLi become similar and even clearly greater than DTFSI.

A solvent-free method that allows thermoplastic solid electrolytes based on poly(ethylene oxide) PEO to be obtained under controlled atmosphere conditions is presented. This method comprises two steps, the first one being the melt compounding of PEO with a filler, able to physically crosslink the polymer and its pelletizing, and the second the pellets’ swelling with an electroactive liquid phase. This method is an adaptation of the step described in previous publications of the preparation of thermoplastic electrolytes by a single melt compounding. In comparison to the single step extrusion methodology, this new method permits employing electroactive species that are very sensitive to atmospheric conditions. The two-step method can also be designed to produce controlled phase-segregated morphologies in the electrolyte, namely polymer-poor and polymer-rich phases, with the aim of increasing ionic conductivity over that of homogeneous electrolytes. An evaluation of the characteristics of the electrolytes prepared by single and two-step procedures is done by comparing membranes prepared by both methods using PEO as a polymeric scaffold and a solution of the room-temperature ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl) imide (EMI TFSI) and the bis(trifluoromethanesulfonyl) imide lithium salt (Li TFSI) as liquid phase. The electrolytes prepared by both methods have been characterized by Fourier transform infrared spectroscopy and optic microscopy profilometry, differential scanning calorimetry, self-creep experiments, and dielectric spectroscopy. In this way, the phase separation, rheology, and ionic conductivity are studied and compared. It is striking how the electrolytes prepared with this new method maintain their solid-like behavior even at 90 °C. Compared to the single step method, the two-step method produces electrolytes with a phase-separated morphology, which results in higher ionic conductivity., This research was funded by H2020-FETOPEN-1-2016-2017 project SALBAGE, Grant Agreement nº766581. F.G. is grateful to CONACYT-SENER for the scholarship granted (CVU 559770/Registro 297710 and S2013/MAE-2800), We acknowledge support by the CSIC Open Access Publication Initiative through its Unit of Information Resources for Research (URICI)

For the sake of simplicity and scalability, we report a methodology to build a superhydrophobic textured upper layer on PVDF/PMMA blend films. The methodology is very easy to implement and does not need any fluorination as last step. In addition, it has been proved that this textured layer works as substrate for lubricant infused surfaces, with outstanding slippery properties. Knowing the importance of controlling the roughness profile to succeed in suitable wetting properties, we perform a thorough study of the roughness parameters by optical profilometry and establish their influence on the final wetting and slippery properties., The authors would like to acknowledge to the Spanish Ministry of Science and Innovation for funding (MAT2016-81001-P and PID2019- 109401 GB-I00). E.A. thanks to Spanish Ministry for the FPI Grant (BES- 2017-080057). The authors are in debt with Dr. J. Marco (IQFR-CSIC) and his team for XPS measurements and valuable discussions

A series of poly(ethylene oxide) (PEO)/lithium trifluoromethanesulfonate (LiTf)/room temperature ionic liquid (RTIL) composite electrolytes has been prepared by melt compounding, using sepiolite modified with d-α-tocopherol polyethylene glycol 1000 succinate (TPGS-Sep) as filler. These electrolytes have been extensively characterized, including thermal stability, relaxations and transitions, rheology, conductivity, ion diffusivity, and salt dissociation. This work shows how the ability of TPGS-S to act as a physical cross-linking site for PEO allows these electrolytes to behave as solids at T > 70 °C, while the abundance of an ionic liquid phase makes the ion diffusion coefficients at 25 °C considerably high, closer to those of a viscous liquid than to those of a solid phase. This combination of rheological and electrical properties, together with their simple and scalable preparation by melt-compounding, makes them a very appealing new class of sustainable electrolytes. This same concept can be applied t...

Electrochemical properties of (polyethylene oxide) (PEO)/lithium trifluoromethanesulfonate (LiTf)/ethylene carbonate (EC)/sepiolite extruded composite electrolytes were studied. Appreciable electrochemical stability of 4.5 V at 70 °C was observed for polymer composite membranes with d -α-tocopherol-polyethylene glycol 1000 succinate-coated sepiolite fillers. Lithium plating/stripping analysis indicated no evidence of dendrite formation with good interfacial properties which were further confirmed by postmortem analysis of the cells. Solid state NMR studies show the presence of two Li + population in the membranes. The feasibility of these electrolytes has been shown with LiFePO 4 cathode materials. Initial discharge capacity of 142 mAh/g was observed remaining at 110 mAh/g after 25 cycles with a coulombic efficiency of 96%. The upscaling of these polymers can be easily achieved by extrusion technique and the capacity can be improved by varying the cathode architecture.

A series of thermoplastic polymer electrolytes have been prepared employing poly(ethylene oxide) (PEO) as a polymer matrix, bis(trifluoromethane sulfonimide) (LiTFSI), and different room-temperature ionic liquids (RTIL) with bis(fluorosulfonyl)imide (FSI) or TFSI anions. This formulation makes them safe and non-flammable. The electrolytes have been processed in the absence of solvents by melt compounding at 120 °C, using sepiolite modified with d-α-tocoferol-polyethyleneglycol 1000 succinate (TPGS-S) as a physical cross-linker of PEO. Several concentrations of RTILs, lithium salt, and TPGS-S have been tested in order to obtain the highest ionic conductivity (σ) without losing electrolytes’ mechanical stability. The materials’ rheology and ionic conductivity have been extensively characterized. The excellent crosslinking ability of TPGS-S makes the electrolytes behave as thermoplastic materials, even those with the highest liquid concentration. The electrolytes with the highest concentrations of FSI anion present a σ over 10−3 S·cm−1 at 25 °C and close to 10−2 S·cm−1 at 70 °C, and notably behave as solids at temperatures up to 90 °C despite over 65 wt % of their formulation being liquid. The electrolytes thus obtained are safe solid thermoplastics prepared by industrially scalable procedures and are suitable for energy storage devices, proving the adequacy of polymer-based materials as solid electrolytes for batteries or supercapacitors., This study was supported by the Comunidad de Madrid (Project Ref. LIQUORGAS-CM, S2013/MAE-2800). Francisco González is grateful to CONACYT-SENER for the scholarship granted (CVU 559770/Registro 297710 and S2013/MAE-2800).

Ion gel polyelectrolytes (IGPs) were prepared by photopolymerization of the synthetic cationic monomers: 1-(2-methacryloyloxy)ethyl-3-butylimidazolium bis(trifluoromethane sulfonyl)imide (IMMATFSI)/bisfluorosulfonylimide (IMMAFSI) or 1-(2-methacryloyloxy)ethyl-1-methylpyrrolidinium bisfluorosulfonylimide (PYRMAFSI)/bis(trifluoromethane sulfonyl)imide (PYRMATFSI) in the presence of bis(trifluoromethane)sulfonamide (LiTFSI) solutions at different concentrations in either 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIFSI), 1-ethyl-3-methylimidazolium bis(trifluorosulfonyl)imide (EMITFSI) or N-propyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide (PMPFSI). The resulting IGPs are thermally stable, easy-to-handle solids wherein the overall ionic conductivity ranges from about 1 to about 10 mS cm at 25 °C. The diffusivity of the ions Li, FSI and TFSI was studied at 25 °C by PGSE-NMR. In IGPs containing imidazolium groups both in the polycationic scaffold and the ionic liquid phase, their large Li ion diffusivities (up to 40 × 10 m s, well above that of the anions) suggest the existence of an important contribution of anion exchange Li transport. To a lesser extent anion exchange may also be occurring in IGPs containing pyrrolidinium groups in the polycationic scaffold and imidazolium groups in the ionic liquid phase and to an even lesser extent in those IGPs with pyrrolidinium in both the polyelectrolyte and the ionic liquid phase. Because of the dimensional and thermal stabilities of IGPs, safety of their components, and their large Li-ion diffusivity, these types of electrolytes appear as excellent candidates for Li and Li-ion batteries., This study was supported by Comunidad de Madrid (project ref. LIQUORGAS-CM, S2013/MAE-2800). Authors are grateful to Francisco Gonz´alez Gonz´alez for the determination of the viscosity of liquid electrolytes.

A polymer/ionic liquid thermoplastic solid electrolyte based on poly(ethylene oxide) (PEO), modified sepiolite (TPGS-S), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and 1-Butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (PYR14TFSI) ionic liquid is prepared using solvent free extrusion method. Its physical-chemical, electrical, and electrochemical properties are comprehensively studied. The investigated solid electrolyte demonstrates high ionic conductivity together with excellent compatibility with lithium metal electrode. Finally, truly Li-LiFePO4 solid state coin cell with the developed thermoplastic solid electrolyte demonstrates promising electrochemical performance during cycling under 0.2 C/0.5 C protocol at 60 ◦C., This study was supported by the Comunidad de Madrid (Project Ref. LIQUORGAS-CM, S2013/MAE-2800). Francisco González is grateful to CONACYT-SENER for the scholarship granted (CVU559770/Registro 297710 and S2013/MAE-2800).

Outstanding Li conductivity and diffusivity have been achieved in free-standing ion gel electrolytes synthesized by in-situ photopolymerization of 1-(2-methacryloyloxy)ethyl-3-butylimidazolium bis(trifluoromethane sulfonyl)imide (IMMA) and/or poly(ethylene glycol) methacrylate (EGMA), in the presence of the room temperature ionic liquids 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMIFSI), 1-butyl-1-methylpyrrolidinium bis(fluorosulfonyl)imide (BMPFSI) and bis(trifluoromethane)sulfonimide lithium salt (LiTFSI). The membranes are easy to handle and thermally stable up to 200 ºC. Those containing IMMA in the polymer chain present liquid-like ionic conductivities (up to 10 mS cm at 25 ºC), and liquid-like Li diffusivities and conductivities (D≈4 × 10 m s, σ≈1.4 mS cm at 25 ºC) unreported so far in a solid electrolyte. D is not only very high but significantly higher than its counteranions’ diffusivity, D or D, a very rare behavior in electrolytes where transport is, in principle, ruled by viscosity. It is proposed that in these polycationic electrolytes the motion of Li occurs via two different transport mechanisms, the well-known viscosity-governed transport and an additional anion-exchange mechanism that enables very fast Li diffusion. This combination has high practical relevance for Li batteries as it implies a high contribution of σ to the overall electrolyte's conductivity, and it constitutes a breakthrough in the design of polymer-based solid electrolytes for Li., This study was supported by Comunidad de Madrid (Project Ref. LIQUORGAS-CM, S2013/MAE-2800). Authors are grateful to Francisco González González for the determination of the liquid electrolytes’ viscosity.

A series of poly(ethylene oxide) (PEO)/lithium trifluoromethanesulfonate(LiTf)/ethylene carbonate(EC)/sepiolite composite electrolytes have been prepared by melt compounding. Neat sepiolite, sepiolite coated with polyethylene glycol and with D-α-tocopherol polyethylene glycol 1000 succinate have been used as fillers, and nanocomposites with different ratio of the components have been prepared. The concentration of EC and LiTf has been progressively increased from low to high values and in this way, electrolytes with conductivities from 2 × 10-6 to 3 × 10-4 S cm-1 at 30 °C have been prepared. Together with conductivity, viscoelasticity has also been studied, evidencing a complex rheological behaviour which depends on the type of filler introduced in the blend. Some of the thermoplastic electrolytes are seen to display a liquid-like conductivity together with solid-like mechanical properties over the melting point of PEO. The solid-like performance is featured by shear moduli crossover G' = G> at 75°C at very low frequencies. This combination of properties makes them appealing starting points for the development of solid polymer electrolytes.

The controlled surface modification of the fibrous clay mineral, sepiolite (Sep), with poly(ethylene glycol) (PEG) and Vitamin E tocopherol polyethylene glycol succinate (TPGS) is presented in this work. Sep, which has a rich surface reactivity because of the presence of silanol groups on its surface, is employed as nanofiller in clay polymer nanocomposites (CPN). It organizes itself into bundles of nanofibers which are difficult to separate from one another unless aqueous gels are prepared under very specific conditions. In the form of an aqueous gel, however, separation of the nanofibers and chemical modification of their surface can be easily done. Sets of very different organosepiolites (OSep) can be obtained in this way. In this work the resulting OSep are characterized in terms of mass incorporation and yields of reaction, specific surface, surface texture, surface water content and thermal stability. As the final purpose of these OSep is the mechanical reinforcement of poly(ethylene oxide) (PEO) based electrolytes highly loaded with ethylene carbonate (EC), blends with PEG or PEO and lithium triflate, with or without EC are prepared and the properties of the final materials are found to be strongly dependent on the type of OSep employed. In particular, examples on the fillers dispersion in the PEO nanocomposites and on their stability in dispersion of PEG/EC blends are described. © 2014 Elsevier B.V.

This work presents a set of sustainable approaches in the preparation of insulators and electrolytes, based on the well-known principles of green chemistry. Attention is paid especially to i) the search of alternatives to chemically crosslinked materials, ii) the elimination of dangerous solvents and iii) the increase of the materials lifetime by reduction of moisture-derived degradation.

This work presents a strategy to obtain plasmonic plastics by conventional large scale polymer processing methods using metal nanoparticles (Au and Ag) supported on sepiolite fibers acting as carriers. Two conventional polymers, polyethylene and polystyrene, have been used as matrices, and composites were prepared up to high inorganic contents. The resulting composites exhibited at all loadings the corresponding optical absorption plasmon bands ascribed to the metal nanoparticles. In addition the sepiolite fibers acting as carriers remarkably improved the thermal stability and produced mechanical reinforcement of the polymer matrices as well as they appear invisible due to the index matching with the matrix. Therefore, highly transparent and robust plasmonic plastics can be easily prepared by industrially scalable processing techniques.

Surface modification reactions on needle-like sepiolite using alkyl and functional silanes have been carried out in the form of aqueous gels. In contrast with modifications in organic solvents, reactions in water make it possible to modify the surface of almost-individual sepiolite fibers and produce either a continuous coating or a nanotexturization of the sepiolite fiber surface, depending on the reaction conditions. This clean procedure substitutes advantageously organic solvent surface modifications and allows the tuning of surface properties such as specific surface area, wetting behavior, and chemical functionalization. A consequence of such tuning is, for example, the excellent dispersion of modified sepiolite nanofibers in a great variety of polymers by routine compounding and processing techniques.

In this work, the characteristics of the β and γ mechanical relaxations, i.e., temperature and relative intensity, of a series of metallocene iPP samples (MPP) are analysed. The hypothesis that the temperature and the intensity of the glass transition (β relaxation) and local sub- T g motions (γ relaxation) are related mainly to chain parameters and morphology has been corroborated. On the one hand, it has been found a critical average isotactic length ( n 1 ) around 30 propylene units, under which the β and γ dynamics are promoted with respect to the α relaxation. On the other hand, it is apparent that the features which determine the degree of constraint within the inter-lamellar region, i.e., the fraction of low- T m crystals, drive the relative intensities of the α, β and γ relaxation processes.

Well-dispersed nanocomposites of LDPE with spherical silica and laminar and fibrous silicates have been prepared by melt compounding with nanofiller compositions ranging from 50 to 5 wt%. Spatial dispersion and size domains of the aggregates in the composites series have been evaluated by electron microscopies (SEM and TEM). The methylene rocking (700–740 cm−1) and bending (1400–1480 cm−1) modes of LDPE in these composites were studied by FTIR spectroscopy. When the nanofiller is present in a 40 or 50 wt%, the amorphous phase of polyethylene adopts a monoclinic arrangement. This arrangement is due to the confinement induced by the nanofillers on the polymer matrix. When the fibrous silicate or the spherical silica are used as nanofillers, a dilution of the concentrated composite or annealing bring about a relaxing of the amorphous structure of the polymer, and the monoclinic-like conformations disappear. When the nanofiller is a laminar silicate, dilution or annealing only partly eliminate the monoclinic-like structure, which remains in all cases an important fraction of the polymeric matrix.

The EPR spectral pattern observed in the bulk polymerization of methacrylic monomers was theoretically investigated by DFT methodology. The conformational analysis of the propagating radical by the rotation around the C α –C β bond, was performed using the B3LYP/6-31G ∗ computational scheme. To obtain accurate values of the isotropic hyperfine coupling constants (hfccs) a higher level protocol, B3LYP/TZVP//B3LYP/6-31G ∗ , was applied. The experimental 13-line spectrum registered at the first stage of the polymerization was assumed to correspond to a free rotating radical in a fluid medium and it was simulated just considering the most stable conformation. The 9-line spectrum registered at high conversions was interpreted in terms of highly hindered rotational conformers frozen in the very viscous medium. This spectrum was well reproduced by a model which considers the sum of the individual spectra of the conformations spread around the most probable. Each of these contributing spectra was obtained on the basis of the computed hfccs for the considered conformations and weighted by his relative Boltzmann population according to the DFT analysis. Besides, the calculated hfccs showed an excellent agreement with those predicted by the Heller–McConnell relationship, which confirms the coherence of the DFT methodology for this kind of calculations.

The posteffects in the polymerization of methyl methacrylate at low monomer conversions are studied. The experimental two-step method consists of a short initial photoinduced polymerization period and subsequent register of the monomer concentration evolution in the dark. After switching off the light, the radical concentration drops sharply, but a nonnegligible concentration of persistent radicals continues the polymerization reaction for long periods of time, yielding ultrahigh molecular weight materials (over 10 000 monomer units). By a fitting procedure applied to the conversion-time curves obtained during the dark period, average values of the termination rate coefficients, , scarcely exceeding 10 000 L mol -1 s -1 , and radical concentrations at the beginning of the postpolymerization about 10 -8 mol L -1 are determined. The reliability of these fitting results is checked by the design of reactions with similar polymerization rate but under steady-state conditions. The molecular weight of the polymers synthesized during the dark period is controlled by the transfer reactions to the monomer and to the initiator. Both transfer reaction constants are estimated by using a method based on the analysis of the instantaneous chain length distribution. The extremely low values obtained by the analysis suggest that the power-law exponents which describe the chain-length dependency of k t should be higher than the unity for long radicals even in dilute solution (i.e., at low monomer conversions).

Pulsed laser polymerization experiments with methyl and dodecyl methacrylate were carried out at various frequencies and temperatures. In addition, the temperature inside the polymerization cell was continuous and automatically registered all along the polymerization time by means of a temperature probe of rapid response time. A significant increase in the reaction temperature was observed for most of the experiments. The temperature profile during the experiments was dependent on the chemical structure of the monomer and on the pulse repetition rate (the higher increase in temperature, the shorter the time between successive laser pulses). The analysis of the well-structured molecular weight distributions of the resulting polymers by size exclusion chromatography (SEC) allowed the determination of the propagation rate coefficients, kp. The kp values showed a decreasing trend when the pulse repetition rate did so. This effect is nowadays being discussed in terms of a long-range chain length dependence of ...

The phosphorescence emission of both naphthalene and pyridine can be used to detect the secondary (β) relaxation of PVC, as this relaxation manifests by a decrease in the emission from the grafted probe at the temperatures at which the local motion at the backbone begins. In this work, an extensive study of the kinetic and spectral features of the phosphorescence of 4-mercaptopyridine, 4-methoxybenzenethiol and 4-mercaptophenol groups as a function of temperature is presented. These three luminescent probes have been grafted onto PVC, with modification levels ranging from 3% up to 46%. The phosphorescence decay from −130 °C up to 30 °C has been followed and both the intensity of the emission and the spectral features have been studied as a function of temperature. The interaction between probes as the concentration increases leads in all cases to the emission from aggregates or excimers, which have features different to those of the isolated probe. Side reactions occur when grafting the hydroxyl containing probe, what also leads to surprising phosphorescence spectral and decay rate features.

Nanocomposites of poly(methyl methacrylate) and 12 nm silica particles have been prepared by a casting procedure which allows the homogeneous dispersion of up to 35 wt% of silica. Twelve nanocomposites with compositions ranging from 1 to 35 wt% have been prepared and studied by Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, Differential Scanning Calorimetry, Thermogravimetric Analysis and Isothermal Chemiluminescence. Thermal stability increases outstandingly as soon as 1 wt% of silica is added to PMMA. This effect is well-known but had not been explained up to now. Of the two main processes which initiate degradation in PMMA, radical formation at labile chain ends and random chain scission, it is the former which disappears in composites with 3 wt% of silica. The origin of the thermal stabilization in these polymer composites is thus the blocking of the PMMA chain end by the silica particle. At the same time, viscous flow decreases progressively, and composites with 20 wt% of silica or over are dimensionally stable even if heated at 300 °C for several hours. The concomitant decrease of viscous flow and increase of low temperature thermal stability shift the temperature range of application of these composites strongly, and the understanding of the silica surface role allows envisaging the control of the behaviour.

This study aims to assess the relative influence of microstructure, molar mass and morphology on the local α relaxation of isotactic polypropylene (iPP). For that purpose, three families of samples have been prepared. The Ziegler–Natta type provides a wide molar mass range where both the isotactic average length ( n 1 ) and the nature of the isotacticity interruptions change according to chain size. The metallocene type allows to analyse also the samples in which molar mass and n 1 are related but the nature of the defects stays the same. Finally, three propylene-like EP copolymers (containing only isolated ethylene units) have been synthesised via metallocene catalysis in order to study samples which combine both relatively high molar masses and short n 1 . Among the factors considered, microstructure and n 1 in particular have been found to drive mainly the quality of the α relaxation. Concerning the intensity, it has been observed that some microstructural features related to n 1 must be fulfilled for this dynamics to take place. Provided this requirements are met, the intensity of the α relaxation depends on the final crystalline distribution resulting from a given molar mass, microstructure and processing conditions.

In the study of the electric properties of electrolytes, the determination of the diffusion coefficients of the species that intervene in the charge transport process is of great importance, particularly that of the free ions (D+ and D-), the only species that contribute to the conductivity. In this work we propose a model that allows, with reasonable assumptions, determination of D+ and D-, and the degree of dissociation of the salt, α, at different concentrations, using the diffusion coefficients experimentally obtained with NMR. Also, it is shown that the NMR data suffice to estimate the conductivity of the electrolytes. The model was checked by means of experimental results of conductivity and NMR diffusion coefficients obtained with solutions of lithium triflate in ethylene and propylene carbonates, as well as with other results taken from the literature.

The incorporation of organic compounds onto the surface of nanoparticles (NPs) differs from the same reactions carried out on macroscopic surfaces in that the former are characterized by surfaces energies much higher than the latter. Consequently, surface stabilization mechanisms of NPs are very active, and among them NP self-aggregation is the first and most important. In NP surface modification, the ability of the experimental conditions to destroy self-aggregation will determine the extent to which the NP surface is modified and so, the modified NP nature. A second consequence of the high-surface free energy is the NP surface avidity to interact chemically or physically with other compounds: NPs readily adsorb water, gases, vapors, or other higher molecular weight substances, and in the particular case of hydroxylated NP, chemical reactivity is both high and rich. This chapter will deal with the surface modification of silica, sepiolite, and polysaccharides. Experimental strategies, resulting organo-NPs, their structure and properties, and frequent uses and applications of them will be reviewed.

Neat poly(9,9-dioctyl-9H-fluorene) (PFO) and composites of PFO and a modified organonanosilica P7 at weight ratios 90/10, 70/30, and 50/50 have been employed to prepare fluorescent and superhydrophobic coatings by spraying onto three different substrates: glass, Whatman paper, and a filtration membrane of mixed cellulose esters. The water repellency of the coatings and their photophysical properties are therein studied. It is found that, irrespective of the substrate and the composite composition, all coatings remain fluorescent. In some of the coatings prepared, confined morphologies are created, which fluoresce with a wavelength distribution resembling that of an ordered planar β-phase. Among the coatings prepared in this work, those with a ratio PFO/P7 of 50/50 are the ones with the strongest chain confinement and the highest surface roughness, being highly emissive at the β-phase wavelengths and also superhydrophobic. Depending on the substrate these materials are also tough and flexible (cellulose based substrates) or display a remarkable light transmittance (glass). A final merit of these multifunctional materials is the simplicity of the preparation procedure, adequate for large surfaces and industrial applications.

The bulk radical polymerization of three methacrylic monomers, butyl, dodecyl, and 3-[tris(trimethylsilyloxy)silyl] propyl methacrylate, were studied in the dark period after previous illumination ...

The oxygen permeability and diffusion coefficients of hydrogel membranes prepared with copolymers of 2-ethoxyethyl methacrylate (EEMA)/2,3-dihydroxypropylmethacrylate (MAG) with mole fraction of the second monomer in the range between 0 and 0.75 are described. Values of the permeability and diffusion coefficients of oxygen are determined by using electrochemical procedures involving the measurement of the steady-state current in membranes prepared by radical polymerization of the monomers. The results obtained for the transport properties were analyzed taking into account the fractional free volumes, the cohesive energy densities and the glass transition temperatures of the hydrogels.

Five predominantly isotactic metallocene polypropylene samples have been synthesized using rac -ethylenebis(indenyl)zirconium dichloride/methyl aluminoxane as catalyst/co-catalyst system. The molecular weight, ranging from 3000 to 41 000 has been determined by viscometry. The chemical and configurational structure have been studied by 13 C NMR and FTIR; melting point and crystallinity by DSC, and γ relaxation, the glass transition and the α relaxation have been determined by DMTA. In these samples, the thermal stability has been studied by recording the chemiluminescence emitted along the thermal oxidation. The results obtained have been compared with previously studied samples of predominantly isotactic Ziegler–Natta polypropylenes of increasing molecular weight.

A series of methacrylic copolymers was prepared by radical polymerization of the monomers 2-ethoxyethyl methacrylate and 2-hydroxyethyl methacrylamide and a small quantity of a cross-linking agent ethylene glycol dimethacrylate. Water swelling of the membranes, mechanodynamical analysis, density measurements, and ATR-FTIR studies were performed on the copolymers. High vacuum pressure techniques were used to evaluate the flow of He, O2, N2, CO2, CH4, CH3CH3, and CH2CH2 through these membranes, and solubility, diffusivity, and permeability coefficients were determined. The effect of the increase of the amount of methacrylamide in the copolymer on transport properties, glass transition, fractional free volume, cohesive energy density, and specific interactions has been studied and is reported in this work.

The changes in the crystalline phase characteristics of a metallocene isotactic polypropylene ( i -PP), during low temperature thermal degradation, have been analysed. This study shows the liability of the higher T m crystalline associations to be affected by the physicochemical changes produced in every stage of the thermo-oxidation. First, a small fraction corresponding to the highest T m crystal entities are involved in the physical reorganization process which takes place in the induction period, before any irreversible chemical change. Second, they are also selectively removed in the autoacceleration stage. This analysis shows not only that the crystalline phase of this i -PP is highly metastable, as it is obtained from the polymerization reaction, but also that the higher the T m of the associations the more liable they are to be affected by oxidation.

Polymer membranes were prepared by radical polymerization of the 1,4,7,10-(tetraoxacyclododecan-2-yl) methyl methacrylate (CR4MA) monomer and a small quantity of a cross-linking agent ethyleneglycoldimethacrylate. High vacuum pressure techniques were used to evaluate oxygen and helium transport through these membranes at temperatures below and above its glass transition temperature, between 0 and 50 °C. The apparent values of both the permeability and diffusion coefficients are unusually low because of the high packing degree of these polymeric membrane materials. The results obtained were also compared with those determined for polymer membranes derived from their open chain counterparts, the polymer derivatives from methacrylate monomers with a number of oxyethylene units in the ester residue variable between 2 and 6, and with a set of other polymers.