Simple weighted density functional approach to the structure of polymers at interfaces

Abstract

A simple weighted density functional approach is employed here for predicting the structure of polymers at interfaces where the polymer molecules are modeled as freely rotating fused-hard-sphere chains with fixed bond lengths and bond angles. The approach treats the ideal gas free energy functional exactly while the excess free energy functional is evaluated using a weighted density approximation. The weight function and the bulk fluid direct correlation function required in the theory are obtained using the Denton-Ashcroft recipe and the polymer reference interaction site model integral equation theory, respectively. The calculated density profiles are shown to be in good agreement with computer simulation results.