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.