Chemical physics of water–water interfaces

A brief review is given on recent progress in experimental and theoretical investigations of the interface between coexisting aqueous phases of biopolymers. The experimental aspects are introduced using results obtained from a model system consisting of aqueous mixtures of nongelling gelatin and dextran. The focus is on the interfacial tension and interfacial electric potential (Donnan potential). These quantities are experimentally accessible and can be shown to be closely related.