INFLUENCE OF CHAIN ARCHITECTURE ON THE THERMODYNAMIC PROPERTIES OF LATTICE POLYMER-SOLUTIONS

Monte Carlo computer simulations have been performed on a three-dimens ional simple-cubic lattice for mixtures of linear and branched chains with monomeric solvent molecules. Mixtures with chains of length 10 an d of length 40 have been considered for both linear and branched archi tectures at a variety of polymer volume fractions. For the internal en ergy of mixing of athermal chains with solvent, the lattice cluster th eory (LCT) is found to give predictions in reasonably good agreement w ith the results of the simulations, especially for short chains. At lo wer temperatures, the theory is not as satisfactory. However, it does prove to be more accurate for branched polymer with solvent than for l inear polymer with solvent. The origins of the changes in the internal energy of mixing are understood in terms of additional internal conta cts made possible by the presence of the branches. The effects of bran ching on the radii of gyration are also presented.