Synthesis of poly(ethylene oxide)-block-poly(methyl methacrylate)-block-polystyrene triblock copolymers by two-step atom transfer radical polymerization

Analysis of individual block length of amphiphilic di- & tri-block copolymers containing poly(ethylene oxide) and poly(methyl methacrylate)

Estimation of individual block lengths and extent of homopolymers.

Durable antifouling polyvinylidene fluoride membrane via surface zwitterionicalization mediated by an amphiphilic copolymer

The antifouling properties of PVDF membrane were remarkably enhanced by facile incorporation of an amphiphilic triblock copolymer PDMAEMA-b-PDMS-b-PDMAEMA and subsequent surface zwitterionicalization.

Synthesis of functionalized poly(vinyl acetate) mediated by alkyne-terminated RAFT agents

Two new xanthates with alkyne functionalities were synthesized for the reversible addition fragmentation chain transfer (RAFT) polymerization of vinyl acetate (VAc).

A novel approach to prepare polymer mixed-brushes via single crystal surface patterning

Single crystals having matrix-dispersed surface morphologies were prepared and characterized.

Different insight into amphiphilic PEG-PLA copolymers: influence of macromolecular architecture on the micelle formation and cellular uptake

One constrain in the use of micellar carriers as drug delivery systems (DDSs) is their low stability in aqueous solution. In this study "tree-shaped" copolymers of general formula mPEG-(PLA)n (n = 1, 2 or 4; mPEG = poly(ethylene glycol) monomethylether 2K or 5K Da; PLA = atactic or isotactic poly(lactide)) were synthesized to evaluate the architecture and chemical composition effect on the micelles formation and stability. Copolymers with mPEG/PLA ratio of about 1:1 wt/wt were obtained using a "core-first" synthetic route. Dynamic Light Scattering (DLS), Field Emission Scanning Electron Microscopy (FESEM), and Zeta Potential measurements showed that mPEG2K-(PD,LLA)2 copolymer, characterized by mPEG chain of 2000 Da and two blocks of atactic PLA, was able to form monodisperse and stable micelles. To analyze the interaction among micelles and tumor cells, FITC conjugated mPEG-(PLA)n were synthesized. The derived micelles were tested on two, histological different, tumor cell lines: HEK293t and HeLa cells. Fluorescence Activated Cells Sorter (FACS) analysis showed that the FITC conjugated mPEG2K-(PD,LLA)2 copolymer stain tumor cells with high efficiency. Our data demonstrate that both PEG size and PLA structure control the biological interaction between the micelles and biological systems. Moreover, using confocal microscopy analysis, the staining of tumor cells obtained after incubation with mPEG2K-(PD,LLA)2 was shown to be localized inside the tumor cells. Indeed, the mPEG2K-(PD,LLA)2 paclitaxel-loaded micelles mediate a potent antitumor cytotoxicity effect.

Functional Polyether-based Amphiphilic Block Copolymers Synthesized by Atom-transfer Radical Polymerization

This review deals with the synthesis, physical properties, and applications of amphiphilic block copolymers based on hydrophilic poly(ethylene oxide) (PEO) or hydrophobic poly(propylene oxide) (PPO). Oligomeric PEO and PPO are frequently functionalized by converting their OH end groups into macroinitiators for atom-transfer radical polymerization. They are then used to generate additional blocks as part of complex copolymer architectures. Adding hydrophobic and hydrophilic blocks, respectively, leads to polymers with amphiphilic character in water. They are surface active and form micelles above a critical micellization concentration. Together with recent developments in post-polymerization techniques through quantitative coupling reactions (‘click’ chemistry) a broad variety of tailored functionalities can be introduced to the amphiphilic block copolymers. Examples are outlined including stimuli responsiveness, membrane penetrating ability, formation of multi-compartmentalized micelles, etc.

Surface Grafting Modification of Silk Fibroin by Atom Transfer Radical Polymerization

In this work, surface modification of silk fibroin was conducted by grafting dimethylaminoethyl methacrylate (DMAEMA) via ATRP to produce well controlled grafting silk. First, the amino groups and hydroxyl groups on the side chains of the silk fibroin reacted with 2-bromoisobutyryl bromide (BriB-Br) to obtain efficient initiator for ATRP. Subsequently, the functional silk fibroin was used as macroinitiator of DMAEMA in 1,2-dichlorobenzene in conjunction with CuBr/N,N,N',N",N" -pentamethyldiethylenetriamine (PMDETA) as a catalyst system. FT-IR characterization of the modified silk substrate showed a peak corresponding to DMAEMA indicating that the polymer had been formed on the silk surface. Following the polymerization, the tertiary amino groups on the grafted silk fibroin were quaternized to produce a large concentration of quaternary ammonium groups, which endowed the silk substrate with potential antibacterial surface. The graft chains were cleaved by acid hydrolysis and analyzed by gel permeation chromatography (GPC). The GPC results indicated that the graft layer were well-controlled.