Synthesis and Surface Attachment of ABC Triblock Copolymers Containing Glassy and Rubbery Segments

The synthesis of an ABC triblock copolymer containing glassy and rubbery segment s was conducted using a combination of living anionic and atom transfer radical polymerizations (ATRP). A poly(dimethylsiloxane) (pDMS) macroinitiator (M n SEC =6200; M w /M n =1.19) was prepared by living anionic ring-opening polymerization, followed by hydrosilation reactions to incorporate 2-bromoisobutyrate end groups for initiation of ATRP. The ATRP of styrene (S) using the pDMS macroinitiator yieleded a diblock copolymer (M n SEC =66730; M w /M n =1.38). Chain extension of the pDMS-b-pS macroinitiator with 3-(dimethyoxymethylsilyl)-propyl acrylate (DMSA) by ATRP yielded an ABC triblock copolylmer. The latter reactive segment was covalently attached to silanol groups on a silicon wafer. The presentation of either glassy pS or flexible pDMS segments of the brushes attached to the surface was reversibly controlled by treatment with selective solvents for each segment.