Poly(ethylene Glycol) Methyl Ether Methacrylate Research Articles

Elastic Single-Ion Conducting Polymer Electrolyte

Single-ion conducting polymer electrolytes (SCPEs) are well recognized being the advanced electrolyte system with increased energy efficiency and prolonged cell lifetime due to their capability to mitigate electrode polarization and reduce electrolyte loss. Fabrication of stretchable SCPEs will definitely benefit the future stretchable batteries/electronics considering the advantageous electrolyte performance of the SCPE based systems, while no one report the SCPEs with specific mechanical performance. Herein, we will report the fabrication of a series of single-ion conducting polymer electrolyte membranes with high flexibility and stretchability. Polydimethylsiloxane (PDMS) network and polyethylene glycol (PEG) side chains are critical in retaining their satisfied mechanical and electrochemical performance. The investigation revealed that the incorporation of poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) plays a significant role in forming the stretchable polymer membranes, which can not only lower the glass transition temperature but also provide additional reactivity. The obtained membranes exhibited 88%-252% elongation before breaks, and the mechanical properties, including Young’s modulus, toughness and tensile strength, are well adjustable by tuning the crosslinking density. Galvanostatic test of the assembled cells using the obtained SCPE member exhibited satisfied cycling performance with capacity retention up to 81.5% after 100 cycles. Figure 1

Biomimetic nanocomposite scaffolds based on surface modified PCL-nanofibers containing curcumin embedded in chitosan/gelatin for skin regeneration

Recently, nanofibrous-hydrogel composites are luring attention for tissue regeneration applications as they mimic soft-tissues' microstructure. Mostly, the electrospun nanofibers based on synthetic polymers such as Polycaprolactone (PCL) are placed in a crosslinked hydrogels. Due to hydrophobic nature of PCL, integration of these nanofibers with the hydrophilic hydrogels of matrix is not sufficient. In this study, we applied Poly(ethylene glycol) methyl ether methacrylate (PEGMA)-surface-modified PCL nanofibers within chitosan-gelatin hydrogels for skin regeneration applications. In addition, curcumin was loaded into PCL nanofibers due to its great impact on skin regeneration process. Fabricated nanofibrous-hydrogel scaffolds were characterized using scanning electron microscopy (SEM), porosimetery, Fourier transform infrared spectroscopy (FTIR), mechanical compression test, and water uptake studies. Curcumin release was investigated using UV/Vis spectrophotometry. In order to study biocompatibility of scaffolds MTT assay and cell culture was performed using L929 cells. FTIR spectra confirmed PEGMA modification of PCL nanofibers. Results of mechanical test determined that surface modified PCL nanofibers improved mechanical strength and modulus of scaffolds. Porosimetery studies showed proper porosity of scaffolds for skin regeneration from 90.43 to 71.48% and pore size of 101–256 μm. Biological test confirmed proper biocompatibility and good cell attachment to the scaffolds. Taken together, the chitosan/gelatin hydrogel incorporating PEGMA modified PCL nanofibers containing curcumin shows great potential for skin regeneration.

Codelivery of doxorubicin and camptothecin by dual-responsive unimolecular micelle-based β-cyclodextrin for enhanced chemotherapy

Tumor microenvironment (TME)-induced drug delivery technology is a promising strategy for improving low drug accumulation efficiency, short blood circulation and weak therapeutic effect. In this work, a dual-responsive (reduction- and pH-responsive) polyprodrug nanoreactor based on β-cyclodextrin (β-CD) was constructed for combinational chemotherapy. Specifically, the dual-responsive star polymeric prodrug was synthesized by atom transfer radical polymerization (ATRP) based on a starburst initiator of β-CD-Br. The obtained polyprodrug contained a hydrophilic chain of poly-(ethylene glycol) methyl ether methacrylate (POEGMA) and a hydrophobic part of camptothecin (CPT) prodrug and poly[2-(diisopropylamino)ethyl methacrylate] (PDPA), denoted as β-CD-PDPA-POEGMA-PCPT (CCDO for short). The obtained CCDO could form stable unimolecular micelles, which could be efficiently internalized by cancer cells. To enhance the curative effect, the anticancer agent doxorubicin (DOX) could be encapsulated into the hydrophobic cavity of the CCDO by hydrophobic-hydrophobic interaction. In vitro drug release studies showed that the obtained CCDO/DOX micelles controlled the release of active CPT and DOX occurring in a reductive environment and at low pH. In vitro cytotoxicity results suggested that the anticancer efficacy of dual-responsive CCDO/DOX micelles was superior to that of CCDO micelles. In addition, in vivo results verified good blood compatibility of the unimolecular micelles. This integrated dual-responsive drug delivery system may solve the low drug loading and poor controlled release problems found in traditional polymer-based drug carriers, providing an innovative and promising route for cancer therapy.

Facile fabrication and biological imaging applications of salicylaldehyde based fluorescent organic nanoparticles with aggregation-induced emission and ESIPT feature

A novel AIE-active fluorogen with large Stokes shift and polymerizable group was synthesized through a one-step conjugation of 4-allyloxy-2-hydroxybenzophenone using hydrazine monohydrate. The obtained 6,6′-((1E,1′E)-hydrazine-1,2-diylidenebis(phenylmethanylylidene))bis(3-(allyloxy)phe-nol) (named as HDPMA) shows AIE feature through excited-state intramolecular proton transfer (ESIPT) mechanism. To examine its potential biomedical applications, the hydrophobic HDPMA was copolymerized with a commercial available, hydrophilic and biocompatible monomer hydrophilic poly(ethylene glycol) methyl ether methacrylate (PEGMA) through reversible addition-fragmentation chain transfer (RAFT) polymerization. The successful synthesis of the HDPMA and final AIE-active poly(PEGMA-co-HDPMA) copolymers was evidenced by a series of characterization techniques. After self-assembly, the amphiphilic poly(PEGMA-co-HDPMA) copolymers could form uniform spherical micelles and showed high water dispersibility, bright yellow-green fluorescence, preeminent photostability, low critical micelle concentration. More importantly, poly(PEGMA-co-HDPMA) FONs show outstanding biocompatibility and low cytotoxicity. With these noticeable superiorities, poly(PEGMA-co-HDPMA) FONs will become promising candidates in biochemical sensing analysis, and cell imaging, even applied in more various important fields.

UV-crosslinked poly(PEGMA-co-MMA-co-BPMA) membranes: Synthesis, characterization, and CO2/N2 and CO2/CO separation

A series of CO2-philic terpolymers were prepared by free radical polymerization using three monomers, poly(ethylene glycol) methyl ether methacrylate (PEGMA), methyl methacrylate (MMA), and 4-hydroxybenzophenone (BPMA), to develop CO2/N2 and CO2/CO separation membranes. The terpolymers, poly(PEGMA-co-MMA-co-BPMA) (PMB), were cast into thin precursor films, which were then crosslinked by a UV-induced photochemical reaction between benzophenone and the alkyl group to produce crosslinked membranes (X-PMB). The gas permeabilities of the X-PMB membranes were influenced by the PEGMA content due to increased CO2 solubility by the polar ether groups of PEGMA. As the content of PEGMA was increased from 60 to 90 wt%, the permeability of CO2 increased from 49.7 to 110.7 barrer. The permeabilities of CO and N2 also increased from 1.92 to 3.68 barrer and from 1.01 to 2.21 barrer, respectively. X-PMB9 with 90 wt% of PEGMA showed the best performance, where CO2 permeability, CO2/N2 selectivity, and CO2/CO selectivity were 110.7 barrer, 49.9, and 30.1, respectively. This membrane performance is comparable to or better than that of a commercially available membrane material, PEBAX, indicating that the X-PMB could be usefully applied to CO2 separation membranes in carbon capture and utilization.

Garnet-doped composite polymer electrolyte with high ionic conductivity for dendrite-free lithium batteries

Abstract Solid polymer electrolytes are promising candidates to replace the extensively used flammable liquid electrolytes in lithium batteries. However, pure polymer electrolytes seldom meet practical requirements because of their relatively low ionic conductivity and poor mechanical properties. Herein, we report a garnet (Li6.4La3Zr1.4Ta0.6O12, LLZTO)-doped composite polymer electrolyte (CPE) membrane for high performance lithium batteries. The CPE is composed of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) and poly(ethylene glycol) methyl ether methacrylate (POEGMA) polymer with the addition of ceramic particles LLZTO. It not only has high ionic conductivity of 1.00 × 10−3 S cm−1 after the activation of liquid electrolyte at room temperature, but also surprisingly restrains the growth of Li dendrites. Its electrochemical stability window is up to 4.7 V (vs. Li+/Li). Moreover, LiFePO4/Li batteries using the CPE exhibit excellent cycling performance and superior rate capability.

The effect of cationic groups on the stability of 19F MRI contrast agents in nanoparticles

ABSTRACTFluorine‐19 (19F)‐based contrast agents are increasingly used for magnetic resonance imaging. Conjugated to polymers, they provide an excellent quantitative imaging tool to detect the movement of the polymeric nanoparticles in vivo as there is no background signal in tissue. One of the challenges is the decline in signal intensity when the conjugated hydrophobic fluorinated functionalities aggregate. Therefore, a new fluorinated monomer was prepared from l‐arginine that carries a 2,2,2‐trifluoroethyl functional group for imaging. The resulting monomer, 2,2,2‐trifluoroethylamide l‐arginine methacrylamide (3FArgMA), was copolymerized with poly(ethylene glycol) methyl ether methacrylate (PEGMEMA), [2‐(2,3,4,6‐tetra‐O‐acetyl‐α‐d‐mannopyranosyloxy)ethyl methacrylate or 1‐O‐methacryloyl‐2,3:4,5‐di‐O‐isopropylidene‐β‐d‐fructopyranose, respectively, using poly(methyl methacrylate) macro‐reversible addition–fragmentation chain transfer polymerization agent. The resulting block copolymers, which varied in 3FArgMA content, were self‐assembled into micelles of hydrodynamic diameters from 25 to 60 nm. The permanently positively charged arginine functionality on the 3FArgMA displayed repulsive forces against aggregation enabling high spin–spin relaxation times (T2) in acidic as well as alkaline solutions. However, the longer poly(ethylene glycol) side functionality in PEGMEMA enabled better steric stabilization (T2~30 ms) while the short fructose side chain was not enough to maintain high T2 values, in particular when a higher 3FArgMA content was used. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1994–2001

Preparation and Characterization of Whey Protein-Based Polymers Produced from Residual Dairy Streams.

The wide use of non-biodegradable, petroleum-based plastics raises important environmental concerns, which urges finding alternatives. In this study, an alternative way to produce polymers from a renewable source—milk proteins—was investigated with the aim of replacing polyethylene. Whey protein can be obtained from whey residual, which is a by-product in the cheese-making process. Two different sources of whey protein were tested: Whey protein isolate (WPI) containing 91% protein concentration and whey protein concentrate (WPC) containing 77% protein concentration. These were methacrylated, followed by free radical polymerization with co-polymer poly(ethylene glycol) methyl ether methacrylate (PEGMA) to obtain polymer sheets. Different protein concentrations in water (11–14 w/v%), at two protein/PEGMA mass-ratios, 20:80 and 30:70, were tested. The polymers made from WPI and WPC at a higher protein/PEGMA ratio of 30:70 had significantly better tensile strength than the one with lower protein content, by about 1–2 MPa (the best 30:70 sample exhibited 3.8 ± 0.2 MPa and the best 20:80 sample exhibited 1.9 ± 0.4 MPa). This indicates that the ratio between the hard (protein) and soft (copolymer PEGMA) domains induce significant changes to the tensile strengths of the polymer sheets. Thermally, the WPI-based polymer samples are stable up to 277.8 ± 6.2 °C and the WPC-based samples are stable up to 273.0 ± 3.4 °C.

Cross-linked porous polymer separator using vinyl-modified aluminum oxide nanoparticles as cross-linker for lithium-ion batteries

A cross-linked porous polymer membrane using vinyl-functionalized aluminum oxide (Al2O3) nanoparticles was prepared and used as a separator for lithium-ion batteries (LIBs). Poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) was first blended with a mixture solution containing poly(ethylene glycol) methyl ether methacrylate (PEGMEMA), vinyl-functionalized Al2O3 nanoparticles (VTMO@Al2O3) as the cross-linker and poly(vinyl pyrrolidone) (PVP) as the pore-forming agent. Subsequently, the membrane was obtained by free radical copolymerization of the above-mentioned mixture and after-treatment. The preparation and properties of the membranes were investigated. It has been found that, under the action of the pore-forming agent of PVP, the obtained membrane (PMAv) had high ionic conductivity (1.37 mS cm−1) at ambient temperature. On account of the existence of the Al2O3 as cross-linking points, the PMAv membrane showed good mechanical strength of 30.4 MPa and excellent thermal stability at 180 °C. Moreover, comparing with the system without PVP or Al2O3 samples, the cell with the PMAv membrane showed the best discharge capacity and most stable capacity retention and cycle performance, indicating that the PMAv membrane is a good polymer separator for LIBs.

All-Aqueous SI-ARGET ATRP from Cellulose Nanofibrils Using Hydrophilic and Hydrophobic Monomers.

An all-water-based procedure for "controlled" polymer grafting from cellulose nanofibrils is reported. Polymers and copolymers of poly(ethylene glycol) methyl ether methacrylate (POEGMA) and poly(methyl methacrylate) (PMMA) were synthesized by surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (SI-ARGET ATRP) from the cellulose nanofibril (CNF) surface in water. A macroinitiator was electrostatically immobilized to the CNF surface, and its amphiphilic nature enabled polymerizations of both hydrophobic and hydrophilic monomers in water. The electrostatic interactions between the macroinitiator and the CNF surface were studied by quartz crystal microbalance with dissipation energy (QCM-D) and showed the formation of a rigid adsorbed layer, which did not desorb upon washing, corroborating the anticipated electrostatic interactions. Polymerizations were conducted from dispersed modified CNFs as well as from preformed modified CNF aerogels soaked in water. The polymerizations yielded matrix-free composite materials with a CNF content of approximately 1-2 and 3-6 wt % for dispersion-initiated and aerogel-initiated CNFs, respectively.

New protein-resistant surfaces of amphiphilic graft copolymers containing hydrophilic poly(ethylene glycol) and low surface energy fluorosiloxane side-chains

Methacryloyl-terminated poly[methyl(3,3,3-trifluoropropyl)siloxane] (PMTFPS-MA) macro-monomers with controlled segment length were designed and synthesized by anionic ring-opening polymerization of 1,3,5-trimethyl-1,3,5-tri(3′,3′,3′-trifluoropropyl)cyclotrisiloxane (F3). Then, a series of novel amphiphilic fluorosiloxane-containing graft copolymers were prepared using PMTFPS-MA, poly(ethylene glycol) methyl ether methacrylate (PEG-MA) and methyl methacrylate (MMA) as the co-monomers, and their surface properties and protein-resistant performance were investigated. It was found that the composition of amphiphilic graft copolymers would play an important role in the protein-resistant properties. When the copolymers contain 65.5 wt% PEO segments and 6.4 wt% PMTFPS segments, the coating surface exhibits strong protein-resistant property and shows almost no protein adsorption on it. Based on the surface analysis of amphiphilic graft copolymer films both in dry and wet conditions, the protein-resistant property of amphiphilic copolymers can be owing to the transition from a hydrophobic surface to hydrophilic surface with highly efficient water-driven PEO surface migration. The PEO segments are utilized to prevent protein adsorption whereas the low surface energy PMTFPS segments are utilized to drive away the adsorbed proteins.

PVDF-based shape memory polymers

P(VDF-co-CTFE)-g-PEGMA copolymers were synthesized via ATRP, using poly(vinylidene fluoride-co-chlorotrifluoroethylene) P(VDF-co-CTFE) as macroinitiator and poly(ethylene glycol) methyl ether methacrylate (PEGMA) as the building block of side chains. Combination of P(VDF-co-CTFE) and PEGMA, resulted in hydrophilic shape memory polymers (SMPs) with tunable thermal and mechanical properties. Melting temperature (Tm) of the soft segments was adjusted around body temperature between 35.3 and 40.9 °C by variation of the soft segment ratio. Copolymers exhibited excellent shape memory properties around Tm of the soft segments and full recovery was achieved within seconds (10 s). This soluble and processable P(VDF-co-CTFE)-g-PEGMA copolymers with SM behavior could potentially play an important role in biomedical applications.

Preparation of PEGylated poly(vinylidene fluoride) porous membranes with improved antifouling property

Antifouling poly(vinylidene fluoride) (PVDF) porous membranes have been fabricated via blending method with poly(ethylene glycol) (PEG)-containing additives and surface grafting technique. Although, it is still a great challenge to simplify the modification processes. Here, a simple process is introduced to fabricate antifouling PVDF porous membranes based on the in situ cross-linking polymerization of poly(ethylene glycol) methyl ether methacrylate (PEGMA) in the casting solutions and the classical non-solvent induced phase separation (NIPS) technique. The surface chemical compositions of the prepared PEGylated PVDF membranes were characterized by x-ray photoelectron spectroscopy (XPS) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The results confirmed that poly(PEGMA) (PPEGMA) chains have been synthesized and immobilized on the membrane surfaces, leading to enhanced hydrophilicity. With increasing PEGMA content, the membrane surfaces changed from the slim fiber-like structure to the sheet morphology with large roughness, meanwhile the finger-like structure elongated in terms of the cross-section morphology. Furthermore, after introducing PPEGMA chains, the flux recovery rate increased to 90.3 ± 2.8% after 3 cycles, indicating improved antifouling ability. The present work provides a convenient method for fabrication antifouling porous membranes for water treatment and purification in large scale.

Versatile Polymeric Microspheres with Tumor Microenvironment Bioreducible Degradation, pH-Activated Surface Charge Reversal, pH-Triggered "off-on" Fluorescence and Drug Release as Theranostic Nanoplatforms.

Facile approach has been developed for the versatile polymeric microspheres with tumor microenvironment bioreducible degradation, pH-activated surface charge reversal, pH-triggered "off-on" fluorescence, and drug release via emulsion copolymerization of glycidyl methacrylate (GMA), poly(ethylene glycol) methyl ether methacrylate (PEGMA), and N-rhodamine 6G-ethyl-acrylamide (Rh6GEAm) with N, N-bis(acyloyl)cystamine) (BACy) as disulfide cross-linker and functionalization. The final PGMA-DMMA microspheres showed excellent cytocompatibility, pH-triggered surface charge reversal at pH 5-6, strong fluorescence only in acidic media, and bioreducible degradation with high reductant level, indicating their promising application as theranostic nanoplatforms for precise imaging-guided diagnosis and chemotherapy. The DOX-loaded PGMA-DMMA microspheres with a drug-loading capacity of 18% and particle size of about 150 nm possessed unique pH/reduction dual-responsive controlled release, with a cumulative DOX release of 60.5% within 54 h at the simulated tumor microenvironment but a premature leakage of <8.0% under the simulated physiological condition. Enhanced inhibition efficacy against HepG2 cells was achieved compared to free DOX.

Matrix-Assisted Regulation of Antimicrobial Properties: Mechanistic Elucidation with Ciprofloxacin-Based Polymeric Hydrogel Against Vibrio Species.

The design of a new drug material through modification of some well-known antibiotics to combat pathogenic bacteria must include a complete understanding of matrix regulation because the human body consists of primarily three types of matrices, that is, solid, semisolid, and liquid, all of which have a tendency to regulate antibacterial efficacy along with the bactericidal mechanism of several antimicrobial agents. Herein, matrix-dependent action of ciprofloxacin-based polymeric hydrogel scaffold was explored against a new species of Vibrio, namely, Vibrio chemaguriensis Iso1 ( V. chemaguriensis), which is resistant to most of the common antibiotics and possess genes that can be linked to pathogenicity. Ciprofloxacin was attached to the polymeric system consisting of hydrophilic polyethylene glycol methyl ether methacrylate (PEGMA) and zwitterionic sulphabetaine methacrylate (SBMA) with an antifouling nature via covalent linkage leading to effective polymer antibiotic conjugates (PACs) with linear and hyperbranched architectures. The hyperbranched PAC was transformed to a polymeric gel exhibiting greater antibacterial efficacy in solid matrix than that of the liquid one with a complete bactericidal effect and rod to spherical switching of bacterial cell followed by chain formation via "dual" contact activity and release mechanism through sustained removal of thiol-terminated ciprofloxacin fragment along with an equilibrium swelling and deswelling process. Lower killing efficacy was displayed in the liquid matrix with an intact cell morphology that is due to lack of forced contact between the cell wall and gel surface as well as entrapment of released bioactive fragment via an additional thick exopolysaccharide (EPS) layer, which represents a great challenge to modern medical sciences.

Linear and Hyperbranched Copolymers of PEG-Based Acrylates and Methacrylic Acid as pH-Responsive Hydrophobic Drug Carriers

The oral administration of pharmaceuticals is typically preferred over other methods due to its non-intrusiveness and convenience of administration. However, the varying chemical environments of the gastro-intestinal tract pose a challenge in ensuring the stability and inertness of a drug compound until it reaches its target. Polymers that are responsive to pH changes have potential as smart materials for the controlled oral administration of pharmaceuticals. In this study, linear and hyperbranched copolymers of methacrylic acid (MAA) and poly (ethylene glycol) methyl ether methacrylate (PEGMEMA) were synthesized by RAFT polymerization. High molecular weight polymers were produced with PDI values close to 1.0. These smart materials underwent phase changes at pH 5.15-5.6. This property enabled the amphiphilicity of the copolymers to be switched on or off. By doing so inin vitrodrug release studies with ibuprofen as the model hydrophobic drug, the copolymers were able to inhibit drug release in simulated stomach conditions to up to 13% while enhancing drug release in simulated intestinal conditions to up to 75% within 6 hours. These indicate that copolymers based on MAA and PEGMEMA have potential as smart materials for drug delivery applications.

Low viscosity and high toughness epoxy resin modified by in situ radical polymerization method for improving mechanical properties of carbon fiber reinforced plastics

In situ radical polymerization method, which is a method for toughening thermosetting resins by modifier polymers radically generated in the curing system of the resins, was applied to epoxy resin for the matrix of carbon fiber reinforced plastic (CFRP) to achieve both high fracture toughness of the cured resin and low viscosity of the resin composition. Benzyl methacrylate (BzMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) were selected as the modifier monomers, and the resulting cured epoxy resin having co-continuous phase separation with the polymerized modifier at a nanometer level showed 2.1 times higher fracture toughness (KIC) than the unmodified cured resin. The modified epoxy resin system was then successfully applied to the fabrication of CFRP by resin transfer molding (RTM) due to its low viscosity in the uncured state. The resultant CFRP system showed 30% increase of the interlaminar fracture toughness (GIC) from the unmodified system.

Facile and effective antibacterial coatings on various oxide substrates

This work reports a facile and effective antibacterial coating for oxide substrates. As a coating material, a random copolymer, abbreviated as poly(TMSMA-r-PEGMA), was synthesized by radical polymerization of 3-(trimethoxysilyl)propyl methacrylate (TMSMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMA). Polymeric self-assembled monolayers of poly(TMSMA-r-PEGMA) were formed on various inorganic oxide substrates, including silicon oxide, titanium dioxide, aluminum oxide, and glass, via the simple dip-coating process. The polymer-coated substrates were characterized by ellipsometry, contact angle measurements, and X-ray photoelectron spectroscopy. The bacterial adhesion on the polymer-coated substrates was completely suppressed compared to that on the uncoated substrates.

Investigation of radical polymerization kinetics of poly(ethylene glycol) methacrylate hydrogels via DSC and mechanistic or isoconversional models

Monomers composed of a polymerizable methacrylate moiety connected to a short poly(ethylene) glycol (PEG) chain are versatile building-blocks for the preparation of “smart” biorelevant materials. Hydrogels based on these PEG methacrylates are a very important class of biomaterials with several applications. The radical polymerization kinetics of two such oligomers, namely poly(ethylene glycol) methacrylate (PEGMA) and poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) was investigated. Experimental polymerization rate and monomer conversion data were measured using DSC operating under non-isothermal conditions, at several constant heating rates, or isothermal, at different constant reaction temperatures. Isoconversional techniques were employed to estimate the variation of the polymerization effective activation energy as a function of the extent of reaction. It was found that isothermal and non-isothermal experiments results in similar trends of the activation energy, whereas by comparison of differential to integral isoconversional methods it was postulated that in non-isothermal polymerization experiments integral methods should not be used. From comparison of the two oligomers employed in the polymerization experiments, it was clear that the presence of the terminal hydroxyl group in PEGMA compared to the methoxy group in PEGMEMA leads to different conversion time profiles and activation energies. In particular, monomer–monomer association through hydroxyl groups results in initially lower activation energy of PEGMA. As polymerization proceeds, the existence of aggregated hydroxyl structures (···OH···OH···OH···) in the PEGMA macromolecular chains result in higher activation energies and a more abrupt increase in the conversion time curve.

Grafting through Method for Implanting of Lysozyme Enzyme in Molecular Brush for Improved Biocatalytic Activity and Thermal Stability

We report a “grafting through” conjugation strategy to improve lysozyme catalytic activity and thermal stability by the synthesis of a synthetic polymer–enzyme hybrid. The lysozyme was first conjugated with glycidyl methacrylate via ring-opening reaction between epoxy groups and lysine residues of the enzyme to synthesize the enzyme macromonomer. The conjugation was followed by free radical copolymerization of the macromonomer with poly(ethylene glycol) methyl ether acrylate (PEGMEA) (Mn = 5000 g/mol) and poly(ethylene glycol) methyl ether methacrylate (PEGMEMA) (Mn = 500 g/mol). We demonstrated that implanting of a single lysozyme molecule in the molecular brush polymer chain resulted a significant improvement of the thermal stability up to 90 °C and 9-time extended half-life for this synthetic enzyme structure. The improved enzyme performance is explained by the crowding effect provided by molecular brush architecture of the synthetic hybrid.