Multilayer theory for adsorption from solution. A general theory for the adsorption of r-mers and its application to flexible tetramers and trimers

Abstract

A statistical mechanical theory for the adsorption from solutions of monomers plus flexible chain r-mer molecules is developed. Its application to the configurational equilibrium of adsorbed tetramers of three different chemical types is outlined. The mean surface area occupied by the odsorbed chain molecules and the mean height of these molecules vary with the concentration of the solution. Adsorption isotherms are presented for size ratios r of the two components from 1 to 4 . For athermal solutions of homogeneous r-mers the results are in fair agreement with the isotherms obtained from the parallel-layer model. The results suggest that, for athermal or nearly athermal systems, experimental adsorption isotherms by themselves are unlikely to provide a sensitive criterion of the configuration of the molecules at the surface.