MICROSCOPIC APPROACH TO INHOMOGENEOUS POLYMERIC LIQUIDS

We discuss a liquid-state theory for the equilibrium structure of inho mogeneous polymeric liquids. The theory consists of an equation for th e;density profile of a liquid in an external potential, which has been derived previously by density functional methods. In general, this eq uation must be solved by sim;lation techniques. However, if the chains are modeled as random walks-which is a reasonable approximation for f lexible polymers,at mel densities-we show that the theory reduces to a set of coupled integral equations which can be solved;numerically. We present results for a single component liquid near a hard wall. Last, we show that, in the Gaussian thread limit, the theory reduces to a f orm that is very similar to Edwards-Helfand-Tagami ''self-consistent f ield'' theory. However, there are important differences between the tw o theories for multicomponent liquids (a blend for example) if the typ es of polymers are structurally dissimilar. (C) 1995 American Institut e of Physics.