Massive field theory approach for polymer chains in confined geometries

摘要

Using the massive field theory approach directly at fixed dimensions d= 3 we calculated the depletion interaction potential and the depletion force between two repulsive, two inert and one repulsive and one inert wall confining a dilute solution of long flexible polymer chains. The obtained calculations for all cases of polymer-surface interactions were performed for an ideal chain and a real polymer chain with excluded volume interactions (EVI) in the wide slit regime. Besides, we used some assumptions which allowed us to estimate the depletion interaction potential in the region of narrow slit. The obtained results are in very good agreement with previous theoretical investigations and with the results of Monte Carlo simulations for the case of two repulsive walls. Taking into account the Derjaguin approximation we obtained good qualitative agreement with the experimental data for the depletion potential between a spherical colloidal particle of big radius and repulsive wall. The obtained results confirm that the depletion interaction potential and the resulting depletion force between two repulsive walls are weaker for chains with EVI than for ideal chains, because the EVI effectively reduces the depletion effect near the walls.