Synthesis of central functionalized asymmetric triblock copolymers for surface modification and switchable surface properties

Well-defined central functionalized asymmetric triblock copolymers (CFABC) were designed as a new type of polymer-brush surface modifier with a short central functionalized black that could form chemical bonds with a suitable substrate surface. A combination of sequential living anionic polymerizati on and polymer modification reactions was used for the synthesis of two CFA BCs: polystyrene-b-poly(4-hydroxystyrene)-b-poly(methyl methacrylate) (3) a nd polystyrene-b-poly(4-urethanopropyl triethoxysilylstyrene)-b-poly(methyl methacrylate) (4). The central block of 3, poly(4-hydroxystyrene), was syn thesized with a protected monomer, p-[(tert-butyldimethylsilyl)oxy]styrene, for the polymerization step, and this synthesis was followed by the hydrol ysis of the silyl protecting group. To obtain polymer 4, the phenol functio nality in 3 was converted to triethoxysilyl groups by a quantitative reacti on with isocyanato propyl triethoxysilane. Gel permeation chromatography an d NMR characterization indicated that the block copolymers possessed contro lled molecular weights and narrow molecular weight distributions. Prelimina ry atomic force microscopy and X-ray photoelectron spectroscopy analysis of the polymer brushes were reported. (C) 2000 John Wiley & Sons, Inc.