A lattice field theory for polymer systems with nearest-neighbor interaction energies

Abstract

We generalize a lattice field theory that formally provides an exact description of the statistical mechanical entropy of nonoverlapping flexible polymers to enable treatment of nearest-neighbor interaction energies. The theory is explicitly solved within an extended mean field approximation for a system of polymer chains and voids, and we also provide mean field results for polymer–solvent–void and binary blend–void mixtures. In addition to recovering the Flory–Huggins mean field approximation for these systems, our extended definition of the mean field approximation contains a set of corrections to Flory–Huggins theory in the form of an expansion in powers of the nearest-neighbor interaction energies.