Synthesis of block copolymers from PDMS macroinitiators

The synthesis of polystyrene-b-polydimethylsiloxane-b-polystyrene (PSt-b-PDMS-b-PSt) copolymers is described. Commercially available difunctional PDMS containing vinylsilyl terminal species was reacted with hydrogen bromide resulting in the PDMS macroinitiators. The terminal alkyl bromide groups were then used as initiators for atom transfer radical polymerization (ATRP) to produce block copolymers. Using this technique, triblock copolymers consisting of a PDMS centre block and polystyrene terminal blocks were synthesized. ATRP of St from those macroinitiators showed linear increases in Mn with conversion, demonstrating the effectiveness of ATRP to synthesize a variety of inorganic/organic polymer hybrids