Synthesis of Amphiphilic Multiblock and Triblock Copolymers of Polydimethylsiloxane and Poly(N,N-Dimethylacrylamide)

The synthesis and spectroscopic characterization of a new family of amphiphilic multiblock and triblock copolymers is described. The synthetic methodology rests on the preparation of telechelic multifunctional and difunctional chain transfer agents easily available in two synthetic steps from commercially available polydimethylsiloxane-containing starting materials. Telechelic polymers thus synthesized are used as macromolecular chain transfer agents in the reversible addition fragmentation chain transfer (RAFT) polymerization of N,N-dimethylacrylamide (DMA) enabling the synthesis of (AB)(n)-type multiblock and ABA-type triblock copolymers of varying compositions possessing monomodal molecular weight distribution. (AB),, multiblock copolymers [(PDMA-b-PDMS)(n)] were prepared with between 52 and 95 wt % poly(dimethylacrylamide) with number average molecular weights (M,) between 14,000 and 86,000 (polydispersities of 1.20-2.30). On the other hand, ABA block copolymers with DMA led to amphiphilic block copolymers (PDMA-b-PDMS-b-PDMA) with M-n values between 9000 and 44,000 (polydispersities of 1.24-1.62). (C) 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7033-7048, 2008