Structure of polymers at interfaces: A density functional approach

Density functional theory has been employed for the investigation of struct ure of polymers at interfaces where the polymer molecules have been modeled as freely jointed tangent hard sphere chains. The excess free energy funct ional has been evaluated within the framework of weighted density approxima tion while the ideal gas free energy functional has been treated in an exac t manner. The weight function required for evaluation of the weighted densi ty is obtained from the Denton-Ashcroft recipe, with the bulk fluid direct correlation function obtained through the polymer reference interaction sit e model integral equation theory. The predictions of the theory is found to be in quantitative agreement with computer simulations for the density pro files.