Synthesis and properties of well-defined poly (dimethylsiloxane)-b-poly(2-hydroxyethyl methacrylate) copolymers

Block copolymers containing dimethyl siloxane and 2-hydroxyethyl methacrylate sequences were synthesized by group transfer polymerization (GTP) of 2-trimethylsilyloxyethyl methacrylate (TMS-HEMA) using silyl ketene acetal terminated poly(dimethylsiloxane) (PDMS) as macroinitiator, followed by hydrolysis of TMS-HEMA to HEMA. The block copolymers were obtained with controlled molecular weight and narrow molecular weight distribution. Trimethylsilyl groups in the P(TMS-HEMA) block could be selectively hydrolyzed without cleaving Si-O bond in PDMS block. The block copolymers formed micelles in methanol, the effective diameters (R_h) of which were in the range of 78 – 110 nm with narrow distribution by dynamic light scattering (DLS). The TEM image showed micelles with a spherical shape. Received: 10 May 2001/Revised version: 23 August 2001/Accepted: 24 August 2001