ADSORPTION OF POLYSTYRENE-BLOCK-POLY(2-CINNAMOYLETHYL METHACRYLATE) BY SILICA FROM BLOCK-SELECTIVE SOLVENT MIXTURES

Polystyrene-block-poly(2-cinnamoylethyl methacrylate) (PS-b-PCEMA) of different block lengths have been synthesized. These polymers were ads orbed via the anchoring of the insoluble PCEMA block on silica, in the brush conformation, from cyclohexane/THF or cyclopentane/THF mixtures when cyclohexane or cyclopentane contents were high. The adsorbed amo unt could be increased or decreased by increasing or decreasing the cy clohexane or cyclopentane content. In a given solvent mixture, number surface coverages rho(infinity) increased as n/m decreased, where n an d m are the numbers of repeat units for the PS and PCEMA blocks, respe ctively. The trend that rho(infinity) increased with decreasing nlm is contradictory to previous experimental observations but can be well e xplained by the scaling relation derived by Marques et al. for block c opolymer adsorption from a micellar solution in the buoy-dominated reg ime.