Abstract
Summary: The synthesis of an ABC triblock copolymer containing glassy and rubbery segments was conducted using a combination of living anionic and atom transfer radical polymerizations (ATRP). A poly(dimethylsiloxane) (pDMS) macroinitiator ($\overline M _{{\rm n}\quad {\rm SEC};}$ = 6 200; $\overline M _{\rm w} /\overline M _{\rm n}$ = 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 yielded a diblock copolymer ($\overline M _{{\rm n}\quad {\rm SEC};}$ = 66 730; $\overline M _{\rm w} /\overline M _{\rm n}$ = 1.38). Chain extension of the pDMS‐b‐pS macroinitiator with 3‐(dimethoxymethylsilyl)propyl acrylate (DMSA) by ATRP yielded an ABC triblock copolymer. 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.
Surface immobilization of pDMS‐b‐pS‐b‐pDMSA triblock copolymer to Si wafer. Treatment of brush with toluene, methanol, or annealing yields brush with hard pS surface. Treatment with hexane selectively solvates pDMS, and the soft layer is presented to the brush surface.
magnified imageSurface immobilization of pDMS‐b‐pS‐b‐pDMSA triblock copolymer to Si wafer. Treatment of brush with toluene, methanol, or annealing yields brush with hard pS surface. Treatment with hexane selectively solvates pDMS, and the soft layer is presented to the brush surface.