STATISTICAL THERMODYNAMICS OF POLYMER SOLUTIONS .7. TRIPLE-CONTACT CONTRIBUTION TO PAIRWISE INTERACTIONS OF LINEAR CHAINS DIFFERING IN MOLECULAR WEIGHT

The influence on the osmotic second virial coefficient of configurations with three contacts between pairs of chain segments has been calculated, in part analytically and in part numerically, for a'bimolecular cluster of linear polymer chains chemically alike but unequal in degree of polymerization. All classes'of contributing chain configurations are included-those with three intermolecular contacts, andthose "with two intermolecular contacts and one intramolecular contact. The new calculations indicate the need for minor quantitative revision of results published earlier for the special case of triple-contact interactions between two identical chains."