ABSTRACT
When solutions of two different polymers in a common solvent are mixed, unless the polymers are structurally very similar, they frequently undergo one or other of two distinct types of interaction, which in each case can lead to phase separation at polymer concentrations above a certain level. From the fundamental molecular viewpoint, studies on interactions between polymers in solution can give further information on the general nature of noncovalent interactions in aqueous systems. These interactions must also be important when there are two polymers present together at an interface, such as the air/water interface, whether they have arrived there by adsorption. From the biological viewpoint, polymer/polymer interactions must occur in cells because of the diversity of biopolymers present there, often at relatively high concentrations. The factors controlling the interactions and effects in such mixtures of polymers must not be expected to be the same as those for a hydrous environment.
