# Dynamics of active filaments in porous media

## TL;DR

This paper investigates how active polymers move in porous media, revealing that flexibility and activity levels cause transitions from localized to diffusive motion, with stiff chains moving freely and flexible ones becoming trapped.

## Contribution

It introduces a model explaining the transition from localization to diffusion based on polymer stiffness and activity, highlighting the role of a continuous time random walk with heavy-tailed waiting times.

## Key findings

- Stiff chains exhibit near-unhindered movement.
- Flexible chains tend to spiral and get trapped.
- Heavy-tailed waiting time distributions lead to subdiffusive behavior.

## Abstract

The motion of active polymers in a porous medium is shown to depend critically on flexibilty, activity and degree of polymerization. For given Peclet number, we observe a transition from localisation to diffusion as the stiffness of the chains is increased. Whereas stiff chains move almost unhindered through the porous medium, flexible ones spiral and get stuck. Their motion can be accounted for by the model of a continuous time random walk with a renewal process corresponding to unspiraling. The waiting time distribution is shown to develop heavy tails for decreasing stiffness, resulting in subdiffusive and ultimately caged behaviour.