Excluded volume effects on tangentially driven active ring polymers

TL;DR

This study investigates how excluded volume effects influence the shape, size, and dynamics of active ring polymers under tangential forces using numerical simulations, revealing distinct behaviors based on interactions and stiffness.

Contribution

It introduces a detailed simulation analysis of active ring polymers considering excluded volume effects, highlighting their impact on conformational and dynamical properties.

Findings

Excluded volume causes swelling in active rings with interactions.

Flexible phantom rings shrink with increased driving force.

Long-time rotational dynamics scale inversely with applied force.

Abstract

The conformational and dynamical properties of active ring polymers are studied by numerical simulations. The two-dimensionally confined polymer is modeled as a closed bead-spring chain, driven by tangential forces, put in contact with a heat bath described by the Brownian multiparticle collision dynamics. Both phantom polymers and chains comprising excluded volume interactions are considered for different bending rigidities. The size and shape are found to be dependent on persistence length, driving force, and bead mutual exclusion. The lack of excluded volume interactions is responsible for a shrinkage of active rings when increasing driving force in the flexible limit while the presence induces a moderate swelling of chains. Internal dynamics of flexible phantom active rings shows activity-enhanced diffusive behavior at large activity values while, in the case of self-avoiding active chains, it is characterized by active ballistic motion not depending on stiffness. The long-time dynamics of active rings is marked by rotational motion whose period scales as the inverse of the applied tangential force, irrespective of persistence length and beads self-exclusion.