PHASE-SEPARATION IN POLYMER-SOLUTIONS

Since the early work of Flory we have understood the causes and main features of the separation of dilute polymer solutions into coexisting phases below the theta point of the polymer-solvent pair. Some issues concerning corrections to the mean-field theory and the reconciliation of theory with experiment remain unresolved, and these are pointed out. In recent years attention has turned to questions about the structure and tension of the interface between those dilute polymer phases. The present status of the scaling theory is reviewed. The application of the theory to the interpretation of the pioneering measurements by Shinozaki et al. of the temperature and chain-length dependence of the interfacial tension in phase-separated solutions of polystyrene in methylcyclohexane, and a more recent test of the scaling theory through measurements of the capillary length of the interface in phase-separated solutions of polymethylmethacrylate in 3-octanone (Xia, Franck and Widom), are described.