The Pincus group is presently concerned with theoretical problems in the physics of multicomponent fluids, including polymer solutions, colloidal dispersions, microemulsions, vesicles, and other surfactant phases. Present activities are mainly focused on biophysics and interfacial interactions. Biophysical considerations include (1) phase behavior of polymers which hydrogen bond to water, e.g. polysaccharides, (2) the interactions between polymers exhibiting helix-coil transitions and lipid membranes, and (3) the role of the interplay between proteins and the membranes in which they are imbedded in determining order-disorder phenomena of membrane bound proteins. Interfacial interaction studies are principally motivated by colloid science and tribology. Current work includes (1) flow and thermal instabilities of polymer layers which are attached or adsorbed on surfaces, (2) interactions between colloidal particles in the presence of mixed solvents, (3) the structure and properties of charged polymers adsorbed or otherwise attached to surfaces, and (4) self assembly of block copolymers to form membranes and microemulsion-like phases.