Lattice models of directed and semiflexible polymers in anisotropic environment

TL;DR

This paper investigates how extended columnar defects in an anisotropic environment affect the conformational properties of directed and semiflexible polymers, revealing length scale competition, phase transitions, and increased polymer stiffness.

Contribution

It introduces lattice models to analyze the impact of anisotropic defects on polymer conformations, highlighting new length scales and stiffness modifications.

Findings

Existence of three characteristic length scales due to anisotropy and stretching.

Identification of a transition point where defect influence balances stretching.

Disorder increases the persistence length of semiflexible polymers.

Abstract

We study the conformational properties of polymers in presence of extended columnar defects of parallel orientation. Two classes of macromolecules are considered: the so-called partially directed polymers with preferred orientation along direction of the external stretching field and semiflexible polymers. We are working within the frames of lattice models: partially directed self-avoiding walks (PDSAWs) and biased self-avoiding walks (BSAWs). Our numerical analysis of PDSAWs reveals, that competition between the stretching field and anisotropy caused by presence of extended defects leads to existing of three characteristic length scales in the system. At each fixed concentration of disorder we found a transition point, where the influence of extended defects is exactly counterbalanced by the stretching field. Numerical simulations of BSAWs in anisotropic environment reveal an increase of polymer stiffness. In particular, the persistence length of semiflexible polymers increases in presence of disorder.