Effect of topology on the collapse transition and the instantaneous shape of a model heteropolymer

TL;DR

This study uses computer simulations to explore how different chain topologies in heteropolymers affect their collapse transition temperature and shape, revealing topology-dependent variations in transition behavior.

Contribution

It introduces a comparative analysis of linear, ring, and trefoil knot topologies in heteropolymers, highlighting the influence of topology and energy polydispersity on collapse transition temperature.

Findings

Transition temperature decreases with increasing topological complexity.

Topology influences the shape parameters across the transition.

Energy polydispersity also affects the transition temperature.

Abstract

The effect of topology on the collapse transition and instantaneous shape of an energy polydisperse polymer (a model heteropolymer) is studied by means of computer simulations. In particular, we consider three different chain topology, namely, linear (L), ring (R) and trefoil knot (T). The heteropolymer is modeled by assigning each monomer an interaction parameter, $\varepsilon_i$, drawn randomly from a Gaussian distribution. Through chain size scaling the transition temperature, $\theta$, is located and compared among the chains of different topogies. The influence of topology is reflected in the value of $\theta$ and observed that $\theta(\text{L}) > \theta(\text{R}) > \theta(\text{T})$ in a similar fashion to that of the homopolymer counterpart. Also studied chain size distributions, and the shape changes across the transition temperature characterised through shape parameters based on the eigenvalues of the gyration tensor. It is observed that, for the model heteropolymer, in addition to chain topology the $\theta$-temperature also depends on energy polydispersity.