Semiflexible polymer in a strip

TL;DR

This paper investigates the thermodynamic behavior of a semiflexible polymer confined in narrow strips, analyzing how wall interactions and bending energy influence density profiles and forces.

Contribution

It provides an exact transfer matrix solution for the model, revealing how bending energy and wall attraction affect polymer density and force profiles.

Findings

Density profile transitions from convex to non-convex as bending energy decreases.

Maximum attractive force occurs when bends are energetically favored.

Range of non-convex density profiles expands with decreasing bending energy.

Abstract

We study the thermodynamic properties of a semiflexible polymer confined inside strips of widths L<=9 defined on a square lattice. The polymer is modeled as a self-avoiding walk and a short range interaction between the monomers and the walls is included through an energy e associated to each monomer placed on one of the walls. Also, an additional energy is associated to each elementary bend of the walk. The free energy of the model is obtained exactly through a transfer matrix formalism. The profile of the monomer density and the force on the walls are obtained. We notice that as the bending energy is decreased, the range of values of e for which the density profile is neither convex nor concave increases, and for sufficiently attracting walls (e<0) we find that in general the attractive force is maximum for situations where the bends are favored.