Synthesis of star polymer poly(ethylene glycol) 3 –poly( N,N ‐dimethyl acrylamide) and its application in protein resistance and separation

A star polymer composed of three poly(ethylene glycol) (PEG) arms and one poly( N,N ‐dimethyl acrylamide) (PDMA) arm (PEG 3 –PDMA) was synthesized by amidation and atom‐transfer radical polymerization. The structure of PEG 3 –PDMA was confirmed by 1 H‐NMR and gel permeation chromatography results. The surface adsorption and protein‐resistance behaviors of the star polymer PEG 3 –PDMA, diblock copolymer PEG–PDMA, and homopolymer PEG were investigated by a quartz crystal microbalance with dissipation. The results indicate that the PEG 3 –PDMA coating could reduce protein adsorption to 13% at least, more effectively than the PEG–PDMA coating; this indicated that the protein‐resistance properties depended on the PEG chain density and surface coverage. If PEG 3 –PDMA were to be used as the physical coating in capillary zone electrophoresis, it could yield a well‐suppressed eletroosmotic flow with greater stability and separate proteins with a lower relative standard deviration (RSD) of protein migration time and a higher separation efficiency than a bare fused‐silica capillary in a broad pH range. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013