Molecular Clustering And Segregation In Sorption Systems

Abstract

The clustering functions interpret adsorption, sorption, and solution thermodynamic behaviour in geometric terms; they cannot predict solution properties. The clustering functions, derived from the cluster integrals of the dilute gas method of statistical mechanics, are free energy functions which depend strongly upon the first derivatives of activities with respect to volume-fractions. Clustering functions greater than minus one are monotone, increasing functions of the tendency of like molecules to cluster. Clustering functions less than minus one denote segregation of like molecules; this segregation increases as the clustering functions become more negative. The clustering functions are applicable to any binary sorption system. This is demonstrated by considering experimental data for several solvent-polymer and gas-polymer systems, a binary solution of liquids of ordinary molecular sizes, three versions of the lattice theory of polymer solutions, monolayer and multilayer adsorption theories, and ideal solution behaviour. © 1972, Walter de Gruyter. All rights reserved.