Polymer-Chain Configurations in Active and Passive Baths

TL;DR

This study compares polymer configurations in active and passive baths, revealing differences in chain properties and conformations, with active baths inducing more bent configurations and higher effective temperatures.

Contribution

It provides experimental analysis of polymer configurations in active versus passive baths, highlighting how activity influences chain properties and conformations.

Findings

Mean chain length and radius of gyration follow Flory's Law in both baths.

Kuhn length is smaller in active baths, indicating higher effective temperature.

Active baths induce more bent chain configurations with a prominent bend.

Abstract

The configurations taken by polymers embedded in out-of-equilibrium baths may have broad effects in a variety of biological systems. As such, they have attracted considerable interest, particularly in simulation studies. Here we analyze the distribution of configurations taken by a passive flexible chain in a bath of hard, self-propelled, vibrated disks and systematically compare it to that of the same flexible chain in a bath of hard, thermal-like, vibrated disks. We demonstrate experimentally that the mean length and mean radius of gyration of both chains obey Flory's Law. However, the Kuhn length associated with the number of correlated monomers is smaller in the case of the active bath, corresponding to a higher effective temperature. Importantly, the active bath does not just simply map on a hot equilibrium bath. Close examination of the chains' configurations indicates a marked bias, with the chain in the active bath more likely assuming configurations with a single prominent bend.