A theoretical and experimental study of interfacial tension of immiscible polymer blends in solution

Abstract

The interfacial properties of demixed solutions of polymer blends are studied. We develop a theory of interfacial concentration profiles taking into account excluded volume effects which are important in solutions. The predictions differ considerably from those obtained by classical mean-field approaches, especially concerning the interfacial thickness. The theory allows us to calculate the interfacial thickness and interfacial tension without any adjustable factor. We measured interfacial tension of demixed poly(styrene)–poly(dimenthylsiloxane) mixtures dissolved in toluene as a function of molecular weight of polymers and monomer concentration. A very good agreement with theoretical predictions is found.