Heterografted PEO–PnBA brush copolymers

A series of P[(HEMA-TMS)-co-PEOMA] graft copolymers with different amounts of incorporated macromonomer grafts were prepared by copolymerization of a PEO macromonomer (PEOMA, MWav=1100 g/mol, DPPEO=23) with 2-(trimethylsilyloxy)ethyl methacrylate (HEMA-TMS) using various initial ratios of the comonomers via atom transfer radical polymerization. After transformation of the HEMA-TMS units to 2-(2-bromopropionyloxy)ethyl methacrylate (BPEM), the resulting P(BPEM-co-PEOMA) copolymers were used as macroinitiators for the controlled polymerization of nBA in a ‘grafting from’ reaction. The resulting densely heterografted brush copolymers with a uniform length of PEO grafts (DPPEO=23) and a range of lengths for the PnBA side chains (DPPnBA=15–60) depending solely on the reaction time. Analysis of the bulk properties showed that the specific architecture of the copolymers suppresses crystallization of the PEO, and consequently leads to amorphous, homogeneous materials.