4-Vinylphenyl Glycidyl Ether: Synthesis, RAFT Polymerization, and Postpolymerization Modifications with Alcohols

Post-Polymerization Modification of Fluoropolymers via UV Irradiation in the Presence of a Photoacid Generator

Fluorinated polymers have unique wettability and protein adsorption properties. The site-specific alteration of these properties could expand their application to different research areas. In this work, a fluorinated homopolymer and two of its copolymers with 4-vinylbenzyl glycidyl ether (VBGE) are synthesized by free radical polymerization. The produced polymers are then used to develop resist formulations by the addition of a photoacid generator. Films of these formulations are exposed to ultraviolet radiation through a binary mask and heated to create the pattern. It is found that the water contact angle values of the exposed films areas are reduced compared to those of the unexposed ones, with the exception of pentafluorophenyl methacrylate (PFMA) homopolymer film. This is attributed to the reaction of the epoxy groups creating x-links and producing hydroxyl groups and the cleavage of the pentafluorophenyl group from the ester group leading to carboxylic acid groups. Both modifications on the exposed areas are verified by FTIR spectroscopy and ToF-SIMS analysis. In addition, the biomolecules adsorption ability of the exposed area is increasing 10-15 times compared to the unexposed one for the PFMA homopolymer and the PFMA/VBGE 1:1 copolymer. Thus, the proposed polymers and patterning procedure could find application to spatially directed immobilization of biomolecules and/or cells onto a surface for both biosensing and tissue engineering purposes.

Main-chain/Side-chain type Phosphine Oxide-Containing Reactive Polymers Derived from same Monomer: Controllable RAFT Polymerisation and ring-opening Polycondensation

This paper reports the synthesis and selective polymerisations of an epoxy-rich phosphine oxide-containing styrenic monomer, namely 4-vinylbenzyl-bis((oxiran-2-ylmethoxy)methyl) phosphine oxide (VBzBOPO). The styryl and epoxy functionalities could be polymerized independently through...

Thermoresponsive Poly(N,N-diethylacrylamide-co-glycidyl methacrylate) Copolymers and Its Catalytically Active α-Chymotrypsin Bioconjugate with Enhanced Enzyme Stability

Responsive (smart, intelligent, adaptive) polymers have been widely explored for a variety of advanced applications in recent years. The thermoresponsive poly(N,N-diethylacrylamide) (PDEAAm), which has a better biocompatibility than the widely investigated poly(N,N-isopropylacrylamide), has gained increased interest in recent years. In this paper, the successful synthesis, characterization, and bioconjugation of a novel thermoresponsive copolymer, poly(N,N-diethylacrylamide-co-glycidyl methacrylate) (P(DEAAm-co-GMA)), obtained by free radical copolymerization with various comonomer contents and monomer/initiator ratios are reported. It was found that all the investigated copolymers possess LCST-type thermoresponsive behavior with small extent of hysteresis, and the critical solution temperatures (CST), i.e., the cloud and clearing points, decrease linearly with increasing GMA content of these copolymers. The P(DEAAm-co-GMA) copolymer with pendant epoxy groups was found to conjugate efficiently with α-chymotrypsin in a direct, one-step reaction, leading to enzyme-polymer nanoparticle (EPNP) with average size of 56.9 nm. This EPNP also shows reversible thermoresponsive behavior with somewhat higher critical solution temperature than that of the unreacted P(DEAAm-co-GMA). Although the catalytic activity of the enzyme-polymer nanoconjugate is lower than that of the native enzyme, the results of the enzyme activity investigations prove that the pH and thermal stability of the enzyme is significantly enhanced by conjugation the with P(DEAAm-co-GMA) copolymer.

Epoxy-functionalised 4-vinylguaiacol for the synthesis of bio-based, degradable star polymers via a RAFT/ROCOP strategy

An epoxy derivative of a naturally occuring vinylphenolic compound, 4-vinylguaiacol, was polymerised using a RAFT/ROCOP strategy and produced ester cross-linked star polymers which could be selectively degraded under acid conditions.

Synthesis of a Fluoromethacrylate Hydroxystyrene Block Copolymer Capable of Rapidly Forming Sub-5 nm Domains at Low Temperatures

A series of poly(pentadecafluorooctyl methacrylate)-block-polyhydroxystyrene (PPDFMA-b-PHS) block copolymers (BCPs) were synthesized via reversible addition-fragmentation chain-transfer polymerization and subsequent deprotection. Because of the high incompatibility between hydroxyl groups and fluoro groups, the interaction parameter (χ) of these BCPs, determined by temperature-resolved small-angle X-ray scattering (SAXS), was extremely high. The χ value of PPDFMA-b-PHS was 0.48 at 150 °C, 16× larger than the χ of polystyrene-block-poly(methyl methacrylate). The microphase behavior of PPDFMA-b-PHS with various volume fractions of PHS block was determined by SAXS, yielding ordered lamellar morphologies with different sizes of domain spacing (d), and further confirmed by transmission electron microscopy. The minimum d obtained was 9.8 nm annealed at a mild temperature for a short time (80 °C for 1 min) by SAXS analysis, indicating the width of each lamellar domains was <5 nm.

Stimuli-Responsive Poly( N-Vinyllactams) with Glycidyl Side Groups: Synthesis, Characterization, and Conjugation with Enzymes

Herein we report the synthesis of new reactive stimuli-responsive polymers by RAFT copolymerization of glycidyl methacrylate and three cyclic N-vinyllactam derivatives. The copolymerization process was thoroughly investigated and the influence of the steric hindrance originating from the monomer structure of cyclic N-vinyllactams on the polymerization process and the properties of obtained copolymers were studied. A series of water-soluble copolymers with variable chemical composition, controlled molecular weight and narrow dispersity ( Đ) were synthesized and their properties are systematically investigated. Experimentally determined cloud points for different copolymers in aqueous solutions indicate shift of lower critical solution temperature (LCST) to lower values with the increase of GMA content in copolymers and increase of the lactam ring size. The obtained reactive stimuli-responsive copolymers can be efficiently used for encapsulation of cellulase in water-in-oil emulsions forming biohybrid nanogels. The enzymes entrapped in nanogels demonstrated significantly improved resistance against harsh store conditions, chaotropic agents, and organic solvents.

Fentanyl Initiated Polymers Prepared by ATRP for Targeted Delivery

The targeted delivery of polymers to neurons is a challenging yet important goal for polymer based drug delivery. We prepared a fentanyl based atom transfer radical polymerization (ATRP) initiator to target the Mu opioid receptor (MOR) for neuronal targeting. We incorporated our recently discovered rigid acrylate linking group into the initiator to retain a high degree of binding to the MOR and grafted random or block copolymers of poly(oligo(ethylene oxide) methacrylate)-block-(glycidyl methacrylate). Trifluoroethanol promoted amine ring opening of the glycidyl methacrylate was used for post-polymerization modification of the fentanyl initiated polymers to attach a near-infrared fluorescent dye (ADS790WS) or to build a targeted siRNA delivery system via modification with secondary amines. We examined the biocompatibility, cellular internalization, and siRNA binding properties of our polymer library in a green fluorescent protein expressing SY SH5Y neuroblastoma cell-line.

Isomeric Effect Enabled Thermally Driven Self-Assembly of Hydroxystyrene-Based Block Copolymers

We demonstrate through isomeric effect the modulation of thermal properties of poly(hydroxystyrene) (PHS)-based block copolymers (BCPs). A minimal structural change of substituting 3HS for 4HS in the BCP results in a drastic decrease in T_g, which in turn enables the thin film assembly of the BCP via thermal annealing. We synthesized a series of poly(3-hydroxystyrene-b-tert-butylstyrene) [P(3HS-b-tBuSt)] and poly(4-hydroxystyrene-b-tert-butylstyrene) [P(4HS-b-tBuSt)] BCPs by sequential anionic polymerization of protected 3HS/4HS monomer and tBuSt followed by deprotection. Measured T_g of P(3HS) was ∼20-30 °C lower than P(4HS) of comparable molecular weights. As a result, thermally driven self-assembly of P(3HS-b-tBuSt) BCPs in both bulk and thin film is demonstrated. For P(4HS-b-tBuSt) thermal annealing in thin-film at high temperatures results in poorly developed morphology due to cross-linking reaction of the 4HS block. The smallest periodicity observed for P(3HS-b-tBuSt) was 8.8 nm in lamellar and 11.5 nm in cylindrical morphologies. The functionality of the 3HS block was exploited to incorporate vapor phase metal oxide precursors to generate sub-10 nm alumina nanowires.

Synergetic effect of the epoxide functional groups in the photocatalyzed atom transfer radical copolymerization of glycidyl methacrylate

Methyl methacrylate (MMA) and glycidyl methacrylate (GMA) were copolymerized by photocatalyzed atom transfer radical polymerization under visible light irradiation. The polymerization was made faster by the epoxide group, which played the role of a reducing agent and thus favored the regeneration of the activator.