New statistical mechanical treatment of systems near surfaces. V. Incompressible blend of interacting polydisperse linear polymers

We consider a lattice model of an incompressible blend of interacting (repu lsive, attractive, or neutral) polydisperse polymers of two species, A and B. The blend is next to an infinite plane surface whose interaction with A can be attractive, repulsive, or neutral. This is the only parameter requir ed to completely specify the effect of the surface on both components of th e blend. We numerically study various density profiles and surface function s, as we move away from the surface, by using the method of Chhajer and Guj rati that has already been successfully applied to study a polymer solution next to a surface. The resulting density profiles show the oscillations th at are seen in Monte Carlo simulations (but with magnitude enhanced and ran ge diminished due to the presence of free volume in simulations), and the e nrichment of the smaller species at a neutral surface. The method is comput ationally ultrafast and can be carried out on a PC, even in the incompressi ble case, when Monte Carlo simulations are not feasible. The calculations u sually take a few seconds to a minute. (C) 2001 American Institute of Physi cs.