ADSORPTION OF END-FUNCTIONALIZED POLYSTYRENE ON MODEL TEXTURED SURFACES

Adsorption of iminium ion end-functionalized polystyrene on model roug h surfaces has been investigated. The model surfaces were prepared by spin coating a solution of colloidal silica beads on aluminum-coated s ilicon surfaces. Atomic force microscopy and scanning electron microsc opy of the surfaces revealed a nearly hexagonal packing of beads. Stat ic secondary ion mass spectroscopy and X-ray photoelectron spectroscop y have been used to measure relative changes in the adsorbed amounts o n the model surfaces compared to a flat surface. We observe a signific ant enhancement of adsorption when the bead to polymer radius (rho/R(g )) is of order unity. For rho/R(g) much greater than 1, the adsorbed a mounts approach that on the smooth surfaces, whereas for rho/R(g) < 1, the adsorption is substantially reduced. The enhancement in adsorptio n is interpreted as a favorable reduction in crowding or stretching en ergy on adsorption, whereas the reduction is understood in terms of to pologically induced steric hindrance to adsorption.