Synthesis of pH-Sensitive Amphiphilic Copolymer Brush by the Combination of ARGET ATRP with ROP and Its Self-Assembly Behavior

Abstract

A random hydrophobic/pH-sensitive copolymer brush poly(polylactide methacrylate-co- methacrylic acid)-b-poly(poly(ethylene glycol) methyl ether methacrylate) (P(PLAMA-co-MAA)-b- PPEGMA) was synthesized by the combination of activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP) with ring opening polymerization (ROP). The chemical structure, molecular weight and polydispersity index were characterized by nuclear magnetic resonance hydrogen spectrum ( 1 H NMR) and gel permeation chromatography (GPC). The reaction conditions of polymerization were optimized and polymer products with controllable molecular weight and narrow distribution were ob- tained. The self-assembly behavior (micelle size, morphology and pH-sensitive properties) of the polymer brush was investigated by dynamic light scattering (DLS) and scanning electron microscopy (SEM). The P(PLAMA-co-MAA)-b-PPEGMA self-assembled micelles were sphere in morphology and with an uniform