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Gelation in the presence of cells with minimum cytotoxicity is highly desirable for materials with applications in tissue engineering. Herein, the naturally occurring polysaccharide pullulan is functionalized with thiolactones that undergo ring-opening addition of amines. As a result, the modified pullulan can be cross-linked with diamines and/or amine-containing biological substrates enhancing the system's versatility (e.g., gelatin and cell-binding ligands GHK/GRGDS). Thiolactone degrees of substitution of 2.5 or 5.0 mol % are achieved, and respective hydrogels exhibit mesh sizes of 27.8 to 49.1 nm. Cell proliferation studies on chosen gels (G' ≅ 500 Pa, over 14 days) demonstrate that for normal human dermal fibroblasts (NHDFs), both gelatin and GRGDS equally support cell proliferation, while in the case of hepatocytes (HepG2), the presence of GRGDS and GHK improve cell proliferation 10-fold compared to gelatin. Cells remain viable and in one instance were successfully encapsulated by in situ gelation, altogether confirming the mild and biocompatible nature of this strategy to produce biogels using biologically active substrates as cross-linkers.

Reactive surfactants (surfmers), which are covalently attached to the surface of sub-micron sized polymer particles during emulsion polymerisation, are applied to tailor the surface functionality of polymer particles for an application of choice. We present a systematic study on the use of oligoglycidol-functionalised styrene macromolecules as surfmers in the emulsion polymerization of styrene. Firstly, we report the impact of the surfmer concentration on the particle size for polymerisations performed above and below the critical micelle concentration. Secondly, we report the influence of the oligoglycidol chain length on the particle size. Thirdly, we conducted experiments to analyse the influence of the surfmer concentration and its chain length on the colloidal stability of the aqueous polystyrene nanoparticles in sodium chloride solutions. We demonstrated that the size of polystyrene particles could be influenced by changing both the surfmer concentration and its chain length. Furthermore, we showed that the colloidal stability of the oligoglycidol-functionalized polystyrene particles is dependent on the particle size, and not directly related to the oligoglycidol chain length. The research work in this paper was carried out within Brightlands Materials Center, a joint research initiative between TNO and the province of Limburg. The work is funded by the Dutch government as well as the province of Limburg. Additionally, the work was partly performed within the Interreg Vlaanderen-Nederland project EnEf and within the Sia RAAK Pro project Window of the Future. Buskens, P (corresponding author), Zuyd Univ Appl Sci, Nieuw Eyckholt 300, NL-6400 AN Heerlen, Netherlands; Hasselt Univ, Inst Mat Res Inorgan & Phys Chem, Agoralaan Bldg D, B-3590 Diepenbeek, Belgium. Mann, D; Buskens, P (corresponding author), Netherlands Org Appl Sci Res TNO, High Tech Campus 25, NL-5656 AE Eindhoven, Netherlands; Brightlands Mat Ctr, Urmonderbaan 22, NL-6167 RD Geleen, Netherlands. 1522736waulthers@zuyd.nl; ryan.vanzandvoort@tno.nl; 1658905castermans@zuyd.nl; jeroen.welzen@chillabs.nl; evelien.baeten@zuyd.nl; kathleen.stout@zuyd.nl; keul@rwth-aachen.de; daniel.mann@tno.nl; pascal.buskens@tno.nl

For the preparation of electrically conductive composites, various combinations of cellulose and conducting materials such as polymers, metals, metal oxides and carbon have been reported. The conductivity of these cellulose composites reported to date ranges from 10−6 to 103 S cm−1. Cellulose nanocrystals (CNCs) are excellent building blocks for the production of high added value coatings. The essential process steps for preparing such coatings, i.e. surface modification of CNCs dispersed in water and/or alcohol followed by application of the dispersion to substrate samples using dip coating, are low cost and easily scalable. Here, we present coatings consisting of Ag modified CNCs that form a percolated network upon solvent evaporation. After photonic sintering, the resulting coatings are electrically conductive with an unprecedented high conductivity of 2.9 × 104 S cm−1. Furthermore, we report the first colloidal synthesis that yields CNCs with a high degree of Ag coverage on the surface, which is a prerequisite for obtaining coatings with high electrical conductivity.

Protecting groups are commonly applied in multi-step molecular syntheses to protect one or multiple functional groups from reacting. After the reaction, they are removed from the molecule. In full analogy to this concept, we report the practical and scalable colloidal synthesis of Au semishells using polyphenylsiloxane protecting patches to prevent part of the surface of polystyrene nanoparticles from being covered with Au. After Au deposition, the patches are removed yielding Au semishells. We anticipate that this strategy can be extended to the synthesis of other types of non-centrosymmetric nanoparticles.

Journal of applied polymer science 12, (2019). doi:10.1002/app.48371, Published by Wiley, New York, NY [u.a.]

Full control over the ceiling temperature (Tc) enables a selective transition between the monomeric and polymeric state. This is exemplified by the conversion of the monomer 2-allyloxymethyl-2-ethyl-trimethylene carbonate (AOMEC) to poly(AOMEC) and back to AOMEC within 10 h by controlling the reaction from conditions that favor ring-opening polymerization (Tc > T0) (where T0 is the reaction temperature) to conditions that favor ring-closing depolymerization (Tc < T0). The ring-closing depolymerization (RCDP) mirrors the polymerization behavior with a clear relation between the monomer concentration and the molecular weight of the polymer, indicating that RCDP occurs at the chain end. The Tc of the polymerization system is highly dependent on the nature of the solvent, for example, in toluene, the Tc of AOMEC is 234 °C and in acetonitrile Tc = 142 °C at the same initial monomer concentration of 2 M. The control over the monomer to polymer equilibrium sets new standards for the selective degradation of poly...

Plasmonics 12(3), 929-945 (2016). doi:10.1007/s11468-016-0345-8, Published by Springer, New York, NY [u.a.]

Polymer chemistry / Royal Society of Chemistry 7(2), 364-369(2016). doi:10.1039/C5PY01566A, Published by RSC Publ., Cambridge

Synthetic amphiphilic copolymers with strong antimicrobial properties mimicking natural antimicrobial peptides were obtained via synthesis of an alternating copolymer of maleic anhydride and 4-methyl-1-pentene. The obtained copolymer was modified by grafting with 3-(dimethylamino)-1-propylamine (DMAPA) and imidized in a one-pot synthesis. The obtained copolymer was modified further to yield polycationic copolymers by means of quaternization with methyl iodide and dodecyl iodide, as well as by being sequentially quaternized with both of them. The antimicrobial properties of obtained copolymers were tested against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus epidermidis, and Staphylococcus aureus. Both tested quaternized copolymers were more active against the Gram-negative E. coli than against the Gram-positive S. aureus. The copolymer modified with both iodides was best when tested against E. coli and, comparing all three copolymers, also exhibited the best effect against S. aureus. Moreover, it shows (limited) selectivity to differentiate between mammalian cells and bacterial cell walls. Comparing the minimum inhibitory concentration (MIC) of Nisin against the Gram-positive bacteria on the molar basis instead on the weight basis, the difference between the effect of Nisin and the copolymer is significantly lower.

Antimicrobial polymers are an attractive alternative to low molecular weight biocides, because they are non-volatile, chemically stable, and can be used as non-releasing additives. Polymers with pendant quaternary ammonium groups and hydrophobic chains exhibit antimicrobial properties due to the electrostatic interaction between polymer and cell wall, and the membrane disruptive capabilities of the hydrophobic moiety. Herein, the synthesis of cationic–hydrophobic polyglycidols with varying structures by post-polymerization modification is presented. The antimicrobial properties of the prepared polyglycidols against E. coli and S. aureus are examined. Polyglycidol with statistically distributed cationic and hydrophobic groups (cationic–hydrophobic balance of 1:1) is compared to (i) polyglycidol with a hydrophilic modification at the cationic functionality; (ii) polyglycidol with both—cationic and hydrophobic groups—at every repeating unit; and (iii) polyglycidol with a cationic–hydrophobic balance of 1:2. A relationship between structure and properties is presented.

Polymers 10(5), 524 (2018). doi:10.18154/RWTH-2018-225705, Published by MDPI, Basel

Antimicrobial polymers are an attractive alternative to low molecular weight biocides, because they are non-volatile, chemically stable, and can be used as non-releasing additives. Polymers with pendant quaternary ammonium groups and hydrophobic chains exhibit antimicrobial properties due to the electrostatic interaction between polymer and cell wall, and the membrane disruptive capabilities of the hydrophobic moiety. Herein, the synthesis of cationic–hydrophobic polyglycidols with varying structures by post-polymerization modification is presented. The antimicrobial properties of the prepared polyglycidols against E. coli and S. aureus are examined. Polyglycidol with statistically distributed cationic and hydrophobic groups (cationic–hydrophobic balance of 1:1) is compared to (i) polyglycidol with a hydrophilic modification at the cationic functionality; (ii) polyglycidol with both—cationic and hydrophobic groups—at every repeating unit; and (iii) polyglycidol with a cationic–hydrophobic balance of 1:2. A relationship between structure and properties is presented.

The functionalization of polymers with phosphorus based reagents is of great interest in the preparation of polymeric materials. In this work we present a straightforward method for the introduction of pendant diethyl phosphate groups into polyglycidol by reaction with diethyl chlorophosphate. The degree of functionalization was controlled by the ratio of the phosphorus reagent to the hydroxyl groups attached to the polyether backbone. Resulting polymers were characterized by 1H, 13C, 31P {1H} NMR spectroscopy, FTIR spectroscopy and SEC analysis. The removal of one and both ethyl groups of the phosphate ester was selectively achieved by reaction with sodium iodide or bromotrimethylsilane, respectively.

The employment of a monomer-specific “on/off switch” was used to synthesize a nine-block copolymer with a predetermined molecular weight and narrow distribution (Đ = 1.26) in only 2.5 h. The monomers consisted of a six-membered cyclic carbonate (i.e., 2-allyloxymethyl-2-ethyl-trimethylene carbonate (AOMEC)) and ε-caprolactone (εCL), which were catalyzed by 1,5,7-triazabicyclo[4.4.0]-dec-5-ene (TBD). The dependence of polymerization rate with temperature was different for the two monomers. Under similar reaction conditions, the ratio of the apparent rate constant of AOMEC and εCL [kpapp(AOMEC)/kpapp(εCL)] changes from 400 at T = −40 °C to 50 at T = 30 °C and 10 at T = 100 °C. Therefore, by decreasing the copolymerization temperature from 30 °C to −40 °C, the conversion of εCL can be switched “off”, and by increasing the temperature to 30 °C, the conversion of εCL can be switched “on” again. The addition of AOMEC at T = −40 °C results in the formation of a pure carbonate block. The cyclic addition of AOMEC to a solution of εCL along with a simultaneous temperature change leads to the formation of multiblock copolymers. This result provides a new straightforward synthetic route to degradable multiblock copolymers, yielding new interesting materials with endless structural possibilities.

Polymers 10(1), 37 (2018). doi:10.18154/RWTH-2018-223455 special issue: "Special Issue "Fluorinated Polymers" / Guest Editor: Prof. Dr. Hideo Sawada, Department of Frontier Materials Chemistry, Graduate School of Science and Technology, Hirosaki, University, Hirosaki, Japan", Published by MDPI, Basel

Terpolymers of homogeneous composition were prepared by free radical copolymerization of butyl or dodecyl methacrylate, 1H,1H,2H,2H-perfluorodecyl methacrylate and maleic anhydride using the continuous monomer addition technique. The copolymerization reactions were performed at 65 °C in the presence of azobisisobutyronitrile as an initiator in a mixture of methyl ethyl ketone and 1,3-bis (trifluoromethyl)benzene. The monomers and initiator are added to the reaction mixture with the same rate they are consumed in 5- and 10-fold excess compared to the initial monomer stock. The obtained terpolymers with molecular weights Mn = 50,000–70,000 are of uniform composition, close to the composition determined in low conversion experiments, proving the principle of the chosen concept. The kinetic data necessary for the design of the continuous addition experiment were obtained from binary copolymerization experiments at low monomer conversion (to avoid compositional drift). In addition, the so-called terpolymerization parameter was determined from ternary copolymerization experiments.

Janus particles are of great research interest because of their reduced symmetry, which provides them with unique physical and chemical properties. Such particles can be prepared from spherical structures through colloidal assembly. Whilst colloidal assembly has the potential to be a low cost and scalable process, it typically lacks selectivity. As a consequence, it results in a complex mixture of particles of different architectures, which is tedious to purify. Very recently, we reported the colloidal synthesis of Au semishells, making use of polystyrene–polyphenylsiloxane Janus particles as an intermediate product (Chem. Commun. 2017, 53, 3898–3901). Here, we demonstrate that these Janus particles are realized through colloidal assembly of spherical glucose-functionalized polystyrene particles and an emulsion of phenyltrimethoxysilane in aqueous ammonia, followed by interfacial polycondensation to form the polyphenylsiloxane patch. Both the polystyrene spheres and the emulsion of Ph-TMS in aqueous ammonia are stabilized by a surfmer—a reactive surfactant. The colloidal assembly reported in this manuscript proceeds with an unexpected high selectivity, which makes this process exceptionally interesting for the synthesis of Janus particles. Furthermore, we report insights into the details of the mechanism of formation of these Janus particles, and apply those to adapt the synthesis conditions to produce polystyrene particles selectively decorated with multiple polyphenylsiloxane patches, e.g., raspberry particles.

Quantification of the stimuli-responsive phase transition in polymers is topical and important for the understanding and development of novel stimuli-responsive materials. The temperature-induced phase transition of poly(N-isopropylacrylamide) (PNIPAm) with one thiol end group depends on the confinement—free polymer or polymer brush—on the molecular weight and on the nature of the second end. This paper describes the synthesis of heterotelechelic PNIPAm of different molecular weights with a thiol end group—that specifically binds to gold nanorods and a hydrophilic NIPAm end group by reversible addition-fragmentation chain-transfer polymerization. Proton high-resolution magic angle sample spinning NMR spectra are used as an indicator of the polymer chain conformations. The characteristics of phase transition given by the transition temperature, entropy, and width of transition are obtained by a two-state model. The dependence of thermodynamic parameters on molecular weight is compared for hydrophilic and hydrophobic end functional-free polymers and brushes.

The use of bio-based building blocks for polymer synthesis represents a milestone on the way to “green” materials. In this work, two synthetic strategies for the preparation of multifunctional polymers are presented in which the key element is the functionality of homoserine lactone. First, the synthesis of a bis cyclic coupler based on a thiolactone and homoserine lactone is displayed. This coupler was evaluated regarding its regioselectivity upon reaction with amines and used in the preparation of multifunctional polymeric building blocks by reaction with diamines. Furthermore, a linear polyglycidol was functionalized with homoserine lactone. The resulting polyethers with lactone groups in the side chain were converted to cationic polymers by reaction with 3-(dimethylamino)-1-propylamine followed by quaternization with methyl iodide.

A highly stable benzimidazolylidene based N-heterocyclic carbene (NHC) ruthenium catalyst was prepared starting with readily accessible starting materials. Under inert gas atmosphere and in air the catalyst showed high activity for the direct synthesis of esters from primary alcohols and of amides from primary alcohols and amines. Di-, tri-, and oligo-amides were obtained by using specific starting materials.

The preparation of multifunctional polymers and block copolymers by a straightforward one-pot reaction process that combines enzymatic transacylation with light-controlled polymerization is described. Functional methacrylate monomers are synthesized by enzymatic transacylation and used in situ for light-controlled polymerization, leading to multifunctional methacrylate-based polymers with well-defined microstructure.

A novel amphiphilic graft copolymer composed of poly(γ-glutamic acid) (γ-PGA) as a hydrophilic backbone and dodecylamine (DOA) as a hydrophobic side chain (γ-PGA-DOA) was successfully synthesized by employing 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) as the coupling reagent. The grafting degree was stoichiometrically controlled by adjusting the feeding amounts of DOA and EDC in the reaction system. γ-PGA-DOA, with a grafting degree of 55%, self-assembled via hydrophobic interactions and formed microparticles (MPs; diameter of 13±3 μm) in an aqueous solution. These MPs possessed functional carboxylic groups and could be further modified with compounds such as drugs, proteins and peptides, and thus have great potential as vaccine carriers. We report the preparation of novel functional microparticles by self-assembly of amphiphilic copolymer composed of poly(γ-glutamic acid) (γ-PGA) as a hydrophilic backbone and dodecylamine (DOA) as a hydrophobic side chain (γ-PGA-DOA). γ-PGA-DOA with a grafting degree of 55% self-assembled by hydrophobic interaction, and formed microparticles (diameter 13±3 μm) in aqueous solution. These microparticles possess functional carboxylic groups, and could be further modified with active compounds such as drugs, proteins and peptides, and thus have great potential as vaccine carriers.

International journal of molecular sciences 14(5), 9722-9736 (2013). doi:10.18154/RWTH-CONV-085528, Published by Molecular Diversity Preservation International, Basel

Glycerol and d , l -homocysteine thiolactone – two bio-based building blocks – were used to prepare a bis-cyclic AA′ monomer (or coupler) with an ethylene carbonate and a thiolactone ring linked by an O-methyl urethane spacer. On reaction of this monomer with diamines at 70 °C poly(amide urethane)s with pendant thioethyl and hydroxymethyl side groups are produced in one step. Monodisperse diamines of low molecular weight (MW), monodisperse amino telechelic poly(ethylene oxide) (MW = 897.10) and polydisperse amino telechelic polytetrahydrofuran (Mn = 1100) were used as amine building blocks. By reaction of the coupler with diamines at room temperature only the thiolactone ring is converted. Consequently, a bis(ethylene carbonate) bis(thiol) is obtained if one equivalent diamine is reacted with two equivalents of coupler. Reaction of this intermediate with a second diamine leads to poly(amide urethane)s with pendant thioethyl and hydroxymethyl side groups and alternating amine building blocks. Post-polymerization modification of thiol side groups leads to polymers with designed properties. The microstructure of the obtained polymers was proven by 1H NMR and Raman spectroscopy; the molecular weights were determined by size exclusion chromatography.

A bifunctional coupler bearing an azetidinium and an aminochlorohydrin group was synthesized in water as solvent starting with piperazine and epichlorohydrin. Conversion of the bifunctional coupler...

Linear aliphatic polyesters having pendant hydroxyl groups were successfully synthesised by polycondensation using scandium triflate as catalyst. A first set of samples was prepared starting with hexane-, octane-, decane-, and dodecanediol and l -malic acid as hydroxyl functional dicarboxylic acid, on the one hand, and succinic acid as non-functional analogue, on the other. A second set of samples was prepared starting with different hydroxytelechelic oligo(e-caprolactone)s, synthesised in a ring opening polymerisation (ROP) initiated by hexanediol using the same catalyst, and reacted with l -malic acid or succinic acid, respectively. The successful reaction was confirmed by nuclear magnetic resonance (NMR) spectroscopy, size exclusion chromatography (SEC), and matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF-MS). The thermal properties of both types of polyesters – with and without pendant hydroxyl groups – were analysed by differential scanning calorimetry (DSC). While all polyesters based on succinic acid are highly crystalline, for the polyesters based on l -malic acid the crystallinity depends on the concentration of pendant hydroxyl groups and on the microstructure. Hence, the influence of the hydroxyl group enables to tailor the crystallinity.

Isocyanate homo telechelic poly(methyl methacrylate-co-allyl methacrylate)s were prepared and used as soft segments for thermoplastic polyurethanes. Copolymerization of allyl methacrylate and methyl methacrylate by RAFT leads to selective conversion of the methacrylate C,C double bonds, leaving the allyl groups in the polymer side chain intact. A hetero telechelic MMA/AMA copolymer (Het-PMMA/AMA, molar ratio of MMA/AMA = 10/1) with a carboxylic acid and a dithiobenzoate terminus was obtained using 4,4-azobis(4-cyano pentanoic acid) as initiator and 4-cyano pentanoic acid dithiobenzoate as chain transfer agent. In a second reaction step the dithiobenzoate terminus is converted to carboxylic acid groups by a radical exchange reaction. The carboxylic acid homo telechelic statistical copolymer (Ca-Hot-PMMA/AMA) is converted quantitatively by reaction with hexamethylene diisocyanate in order to form isocyanate homo telechelic copolymer (Is-Hot-PMMA/AMA). Last the obtained soft segments were used for polyurethane synthesis. The well-defined polymer structures are characterized by SEC, Raman, and 1H NMR spectroscopy.

Polymers 8(10), 372 (2016). doi:10.3390/polym8100372 special issue: "Special Issue "Enzymatic Polymer Synthesis" / Guest Editor: Dr. Katja Loos, Macromolecular Chemistry and New Polymeric Materials, Zernike Institute for Advanced Materials, University of Groningen", Published by MDPI, Basel

The synthesis and modification of thiol functionalized poly(meth)acrylates using a straightforward reaction concept that consists of an enzymatically catalyzed monomer synthesis, free radical polymerization and post-polymerization modification is presented. The well-known enzymatic transacylation of methyl acrylate and methyl methacrylate that runs under mild and environmentally friendly conditions was used to synthesize thiol protected acrylic and methacrylic monomers. Upon free radical polymerization and subsequent removal of protection groups, polymers with pendant thiol groups are obtained, which, in turn, can react in situ with Michael acceptors to form thiol-ene reaction products. The exceptional advantage of the proposed method is that upon removal of the enzyme from the monomer mixture, the polymerization, deprotection of thiols and subsequent Thio-Michael-type addition reaction can be conducted in one pot without purification of the intermediate products. Furthermore, the different reactivities of acetyl and benzoyl protection groups in lipase catalyzed reactions are discussed.

Starting with asymmetric A,A′-carbonate couplers A1–A4 via substitution reaction with primary amines at low temperatures (0–25 °C) followed by addition reaction with primary amines at higher temperatures (60–80 °C), bis(functional) compounds with a free hydroxyl group were prepared. These compounds were used: (i) as initiators for ring-opening polymerization of e-caprolactone; (ii) as substrate for the preparation of an ATRP initiator for MMA polymerization; (iii) as substrate for the preparation of an activated carbonate for grafting of an amine end-functionalized linear polymer (Jeffamine® M1000). Via modifications (i)–(iii), amphiphilic end-functionalized poly(e-caprolactone)s, poly(methyl methacrylate)s, and polyethers were prepared, respectively.

New polyhydroxyurethanes (PHUs) were prepared from (5-ethyl-2-oxo-1,3-dioxan-5-yl)methyl phenyl carbonate and (5-ethyl-2-oxo-1,3-dioxan-5-yl)methyl imidazolyl carbonate with ethylenediamine, tetramethylenediamine and hexamethylenediamine. These PHUs were characterized by SEC, DSC, TGA, NMR spectroscopy and IR spectroscopy, and the results were compared to previously reported results of PHUs prepared from phenoxycarbonyl-oxymethyl ethylene carbonate with corresponding diamines.

Full control over the ceiling temperature (Tc) enables a selective transition between the monomeric and polymeric state. This is exemplified by the conversion of the monomer 2-allyloxymethyl-2-ethyl-trimethylene carbonate (AOMEC) to poly(AOMEC) and back to AOMEC within 10 h by controlling the reaction from conditions that favor ring-opening polymerization (Tc > T0) (where T0 is the reaction temperature) to conditions that favor ring-closing depolymerization (Tc < T0). The ring-closing depolymerization (RCDP) mirrors the polymerization behavior with a clear relation between the monomer concentration and the molecular weight of the polymer, indicating that RCDP occurs at the chain end. The Tc of the polymerization system is highly dependent on the nature of the solvent, for example, in toluene, the Tc of AOMEC is 234 °C and in acetonitrile Tc = 142 °C at the same initial monomer concentration of 2 M. The control over the monomer to polymer equilibrium sets new standards for the selective degradation of polymers, the controlled release of active components, monomer synthesis and material recycling. In particular, the knowledge of the monomer to polymer equilibrium of polymers in solution under selected environmental conditions is of paramount importance for in vivo applications, where the polymer chain is subjected to both high dilution and a high polarity medium in the presence of catalysts, that is, very different conditions from which the polymer was formed.

Well-defined polystyrene-block-polyglycidol (PS-b-PG) block co-polymers of various composition were prepared in two steps: (i) sequential anionic polymerization of styrene in benzene initiated with...

Two copolymers, P(PCEMA-co-MMA) and P(t-BMA-block-PCEMA), were prepared via ATRP using 2-(phenoxycarbonyloxy)ethyl methacrylate (PCEMA) as reactive monomer and methyl methacrylate (MMA) or tert-butyl methacrylate (t-BMA) as co-monomers. Alternatively phenoxycarbonyloxy decorated polymethacrylates were obtained via polymer analogous reaction: P(HEMA) was reacted with phenyl chloroformate to yield P(PCEMA). The highly reactive phenoxycarbonyloxy groups were used for polymer analogous reactions with nucleophiles to obtain polymers with ionic/hydrophilic and hydrophobic side groups. Different amines with long alkyl chains or tertiary amine groups were reacted with phenoxycarbonyloxy decorated polymers and subsequently reacted with methyl iodide to obtain amphipathic polymers with bacteriostatic properties.

Well defined linear and 3-, 4-, and 6-arm-star shaped polyglycidols were obtained via anionic ring-opening polymerisation of ethoxyethyl glycidyl ether using 3-phenyl-1-propanol, trimethylolpropane, di(trimethylolpropane, and dipentaerythrite as initiator followed by the removal of the acetal protection group via acid catalysed hydrolysis. The microstructure and architecture of the polymers was proven by NMR spectroscopy, size exclusion chromatography and MALDI-TOF-MS. Multifunctional initiators for the atom transfer radical polymerisation were obtained by esterification of the hydroxyl groups of the polyglycidols with α-bromoisobutyryl bromide. Kinetic studies of the ATRP of tert-butyl acrylate and methyl acrylate revealed a controlled synthesis of linear and multi-arm-star polyglycidols of different architecture grafted with polyacrylate side arms.

Linear and star shaped polyglycidols (synonym with polyglycerols) are prepared in a controlled ring opening polymerization of protected glycidols. Beside the molar mass and the polydispersity, the architecture of the polyglycidols is controlled by using mono- and multifunctional mono- and polydispers initiators. Copolymers of dissimilarly protected glycidols as well as copolymers with nonfunctional oxiranes were prepared by means of anionic polymerization while copolymers of protected glycidol with tetrahydrofuran were prepared by means of cationic polymerization. Polyethers with functional groups in the side chains (functional polyethers) with special emphasis on polyglycidols (containing hydroxymethyl groups in the side chains) were used to prepare multifunctional polymers and (hetero)grafted polymer brushes via chemical and enzyme catalyzed reaction. The potential of poly(glycidol-graft-e-caprolactone)-co-glycidol) prepared via enzyme catalyzed grafting of polyglycidols using e-caprolactone as a monomer and Lipase B from Candida antarctica as a catalyst is presented. Finally, comparative degradation studies of densely and loosely grafted polyglycidols are presented and discussed. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3209–3231, 2009

Poly(ester amide)s (PEAs) were prepared from diols, amino alcohols and diamines with an in-built amide group via polycondensation with 1,4-butanediol and dimethyl adipate. The tailor-made monomers were synthesized by ring opening of e-caprolactone and e-caprolactam using 1,4-diaminobutane, 4-aminobutanol and 2-aminoethanol. PEAs having an isolated amide bond or two or three consecutive amide bonds in the poly(butylene adipate) (PBA) backbone, respectively, were obtained via melt polycondensation. The concentration of the amide groups in the PEAs was varied by the amount of preformed α,ω-diamines, amino alcohols or diols introduced in the feed. A simple synthetic route to these preformed monomers and the corresponding PEAs is described. The products were obtained in high purity and high yields.

Dalton transactions 44(39), 17409-17414(2015). doi:10.1039/C5DT01358E, Published by Royal Society of Chemistry, London

The bis(ethylene carbonate) monomers 3,4-O-isopropylidene-D-mannitol-1,2:5,6-dicarbonate (2) and D-mannitol-1,2:5,6-dicarbonate (1) were prepared fromD-mannitol in yields of 81 and 74%, respectively. These AA-type monomers were reacted with α, ω-diamines (H2N—(CH2) x –NH2; x = 2–10 and 12) as BB-type monomers in the sense of a polycondensation reaction. The molecular weights of the polyurethanes with pendant hydroxy groups obtained were determined by means of gel permeation chromatography in dimethylacetamide/LiCl and are in the range of 20 × 103 to 87 × 103 with polydispersity indices of ca. 1.6. The polyurethanes show primary and secondary hydroxy groups with a ratio of ca. 15:85. This is a consequence of the different direction of opening of the substituted ethylene carbonate ring which results in structurally isomeric repeating units. The polyurethanes obtained from 2 and diamines with two free hydroxy groups and two protected hydroxy groups in the repeating unit are semicrystalline materials with mel...

Branched poly(ethylene imine) (PEI) with primary, secondary and tertiary amine groups in a ratio of 1:2:1 was specifically functionalized at the primary amine groups with quaternary ammonium groups and C12 alkyl chains. This reaction was performed by treatment of PEI with functional cyclic carbonates, i.e. trimethyl-(2-oxo-[1,3]dioxolan-4-ylmethyl)-ammonium iodide (1) and (2-oxo-1,3-dioxolan-4-yl)methyl dodecylcarbamate (2), under mild conditions in aprotic dipolar solvents. For determination of the reaction conditions model reactions of the functional carbonates with primary amines were performed in different solvents including water. In the presence of water side-reactions, such as hydrolysis of the ethylene carbonate ring, take place and have to be avoided. The structure of the obtained polymers was studied by means of 1H- and 13C-NMR spectroscopy, and the thermal properties were determined by means of DSC and TGA measurements. The PEI-functionalized polymers with long alkyl chains and quaternary ammon...

Temperature-induced phase transition parameters of responsive free polymer and brushes onto nanoparticles are measured using high-resolution magic-angle sample spinning (HRMAS) NMR spectroscopy. To this purpose, a two-state statistical model of temperature dependence of thermodynamic observables is developed and applied to obtain parameters which characterize the process of temperature-induced phase transition of stimuli-sensitive polymers. In this investigation the thermodynamic observable is the integral intensity of the 1H HRMAS NMR spectrum peaks and the derived thermodynamic parameters are transition temperature and transition entropy. This approach is applied to investigate the dependence of temperature-induced coil-to-globule transition of poly(N-isopropylacrylamide), (PNIPAm), asymmetric end functionalized with benzyl and thiol groups (Bn–PNIPAm–SH) on molecular weight in the range 3600–30 000 g mol–1 in aqueous solutions. The characteristics of the phase transition represented by transition temperature, and transition entropy are compared to that of Bn–PNIPAm–SH brushes onto gold nanorods in the same range of molecular weight. The method used for measuring the characteristics of phase transition is based on transverse magnetization relaxation (T2) spin-echo enhance editing of the integral intensities of the 1H HRMAS NMR spectra. This NMR observable reflects changes in transverse relaxation times as an indicative of the polymer chains conformations and dynamics reached in the process of temperature-induced phase transition.

We present a facile and versatile platform approach for the synthesis of submicrometer-sized hybrid particles based on an oil-in-water emulsion. These particles comprise organosiloxanes and/or organosilsesquioxanes formed via hydrolysis and polycondensation of alkyl- or aryltrimethoxysilane, and polystyrene or poly(methyl methacrylate) formed through radical polymerization of styrene and methyl methacrylate, respectively. In this synthesis, the alkyl- or aryltrimethoxysilane fulfills three different roles: (i) it is part of the oil phase, (ii) serves as monomer for the formation of the organosiloxane network, and (iii) forms a surface active species that stabilizes the emulsion. Size, composition and architecture of the resulting hybrid particles are programmable in this synthetic approach, as demonstrated for the combination phenyltrimethoxysilane/styrene. The versatility of the approach is demonstrated by preparing hybrid particles based on following precursor/monomer combinations: phenyltrimethoxysilane/methyl methacrylate, methyltrimethoxysilane/styrene, (3-acryloxypropyl)-trimethoxysilane/styrene and (3-mercaptopropyl)trimethoxysilane/styrene. Latter combination yields hybrid spheres with thiol groups suited for further functionalization.

Polymers 6(5), 1618-1630 (2014). doi:10.18154/RWTH-CONV-088937, Published by Molecular Diversity Preservation International, Basel

We present the synthesis of glucose-functionalized polystyrene particles through emulsion polymerisation using glucose acrylate as reactive surfactant. Additionally, we present the selective deposition of silver on the surface of these particles yielding well-defined polystyrene-silver composites.

Full Paper: Four different types of polydepsipeptide-polyether block copolymers were synthesized via ring-opening polymerization of 3(S)-sec-butylmorpholine-2,5-dione (BMD) in the presence of hydroxytelechelic poly-(ethylene oxide) (PEO) with stannous octoate as a catalyst. The polymers were an AB block copolymer, an ABA block copolymer, an (A) 2 B star shaped copolymer and an (A) 2 B(A) 2 copolymer, where A is a poly[3(S)-sec-butyl-morpholine-2,5-dione] (PBMD) and B a poly(ethylene oxide) block. The molar ratio of BMD to PEO was varied to obtain copolymers with different weight fractions of PBMD blocks ranging from 59.8 to 96.7 wt.-%, The crystallinity of the PEO phase in the copolymers decreases in the following order: AB > (A) 2 B > ABA > (A) 2 B(A) 2 . The static contact angle θ decreases with increasing PEO content in the block copolymers.

Macromolecules 46(15), 6159 - 6168 (2013). doi:10.1021/ma4008797, A semicrystalline/liquid-crystalline diblock copolymer formed by complexation of a wedge-shaped ligand, 2-(3′,4′,5′-tris(octyloxy)benzamido)propanoic acid, with P2VP–PEO copolymer was studied. The P2VP complex forms layers with a liquid-crystalline (LC) order causing phase segregation of the PEO block. The molar ratio ligand/pyridine (x) determines the strength of segregation between the blocks and the microphase morphology. For x ≥ 0.5, PEO forms cylinders within the LC matrix. The phase separation strongly shifts the crystallization temperature to lower values and forces PEO to crystallize within the block copolymer cylinders. In thin films, alignment of the smectic layers parallel to the substrate induces homeotropic orientation of the PEO cylinders. Inside these cylinders, the crystalline stems preferentially orient along the smectic normal. For x ≤ 0.33, PEO forms crystalline lamellae within the LC matrix and crystallization dominates the final structure., Published by Soc., Washington, DC

The extracellular medium-chain-length polyhydroxyalkanote (MCL-PHA) depolymerase from an isolate identified as Streptomyces venezuelae SO1 was purified to electrophoretic homogeneity and characterized. The molecular mass and pI of the purified enzyme were approximately 27 kDa and 5.9, respectively. The depolymerase showed its maximum activity in the alkaline pH range and 50 °C and retained more than 70 % of its initial activity after 8 h at 40 °C. The MCL-PHA depolymerase hydrolyzes various p-nitrophenyl-alkanoates and polycaprolactone but not polylactide, poly-3-hydroxybutyrate, and polyethylene succinate. The enzymatic activity was markedly enhanced by the presence of low concentrations of detergents and organic solvents, being inhibited by dithiothreitol and EDTA. The potential of using the enzyme to produce (R)-3-hydroxyoctanoate in aqueous media or to catalyze ester-forming reactions in anhydrous media was investigated. In this sense, the MCL-PHA depolymerase catalyzes the hydrolysis of poly-3-hydroxyoctanoate to monomeric units and the ring-opening polymerization of β-butyrolactone and lactides, while e-caprolactone and pentadecalactone were hardly polymerized.

On the basis of commercially available trimethylolpropane (TMP) three six-membered ring carbonates were prepared, substituted with reactive side groups: a chloroformate (2a), an imidazolyl carbamate (2b) and a phenyl carbonate (2c). Their synthesis and characterizations are described and compared to known ring carbonates with reactive side groups. Starting from 2a-c orthogonal couplers 3a and 3b were synthesized for conversion under mild reaction conditions. In a model reaction 2-azidoethyl 2-N-acetylamino-2-deoxy- -D-glucopyranose and tertbutyl- N-(3-aminopropyl) carbamate were linked with coupler 3a via a 1,3-dipolar cycloaddition and a nucleophilic ring-opening reaction. This coupling principle can be used for the preparation of multifunctional polymers or surface coatings at ambient conditions.

Alkalimetal salts (Li+, K+) and metal-free salts ([(CH3)2N]3S+, Bu4N+) of hydroxytelechelic poly(THF) were used as initiators for the anionic ring-opening polymerization of 2,2-dimethyltrimethylene carbonate (DTC). With both systems triblock copolymers were obtained with a monomodal distribution of molecular weights, with one exception. Copolymers with equal length of the poly(DTC) block and increasing molecular weight of the initiating block show the following features: (i) no influence at low molecular weights of the initiator ( M n = 650 ); (ii) plasticizing effect in the range 1000 M n ; (iii) two phase systems at M n > 2600 . The triblock structure of the copolymers was established by degradation of the poly(THF) middle block under acidic conditions with subsequent 1H-NMR and GPC analysis.

Materials / Molecular Diversity Preservation International 3(5), 3369-3384 (2010). doi:10.3390/ma3053369 special issue: "Special Issue 'Advances in Surface Coatings' / Guest Editor: Frank A. Müller", Published by MDPI, Basel