ATRP Synthesis of Amphiphilic Random, Gradient, and Block Copolymers of 2-(Dimethylamino)ethyl Methacrylate and n-Butyl Methacrylate in Aqueous Media

Amphiphilic random, gradient, and block copolymers of 2-(dimethylamino)ethyl methacrylate (DMAEMA) and n-butyl methacrylate (BMA) were synthesized by atom transfer radical polymerization (ATRP) in water/2-propanol mixtures using a methoxy-poly(ethylene glycol) (MPEG) (M n = 2000) macroinitiator. Kinetic studies indicate that the copolymerization is well controlled with molecular weights increasing linearly with conversion. Copolymers with molecular weights up to M n = 34 000 and low polydispersities (M w/M n = 1.11−1.47) were prepared. The reactivity ratios were calculated for the copolymerizations catalyzed by CuBr/bpy, (r DMAEMA = 1.07, r BMA = 1.24). The thermosensitivity and aggregation properties of the random, gradient, and block copolymers significantly depended on the architecture of the copolymers. The lower critical solution temperature of MPEG-b-PDMAEMA84 was 38 °C (5 wt % in water).