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 adsorbed 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 amount could be increased or decreased by increasing or decreasing the cyclohexane or cyclopentane content. In a given solvent mixture, number surface coverages ρ ∞ increased as n / m decreased, where n and m are the numbers of repeat units for the PS and PCEMA blocks, respectively. The trend that ρ ∞ increased with decreasing n / m is contradictory to previous experimental observations but can be well explained by the scaling relation derived by Marques et al. for block copolymer adsorption from a micellar solution in the buoy-dominated regime.