GRADIENT ENERGY PARAMETERS FOR POLYMER-POLYMER-SOLVENT SYSTEMS AND THEIR APPLICATION TO SPINODAL DECOMPOSITION IN TRUE TERNARY-SYSTEMS

The entropic gradient contributions to the free energy of nonuniform polymer–solvent systems and polymer–polymer–solvent systems have been obtained using a mean field approach. The results for a polymer–polymer–solvent system reduce to those of de Gennes for a polymer–polymer system at the appropriate limit. The binary results for a polymer–solvent system predict interfacial tensions that are systematically high but closer to experiment than those predicted by the earlier model of Balsara and Nauman. The ternary results have been applied to spinodal decomposition in polymer–polymer–solvent systems. The linear theory predicts a decrease in the domain size with increasing quench depth. Also, it predicts an increasing domain size with an increase in compatibility between the two polymers for any given quench depth. Copyright © 1990 John Wiley & Sons, Inc.