An active filament on a cylindrical surface: morphologies and dynamics

TL;DR

This study uses Brownian dynamics simulations to explore how active polymers behave on cylindrical surfaces, revealing various conformations, motion types, and the influence of physical parameters on their dynamics and phase behavior.

Contribution

It systematically investigates the effects of active force, chain properties, and surface curvature on polymer conformations and dynamics, providing new insights into active polymer behavior on curved surfaces.

Findings

Identifies three conformations: spiral, helix-like, and rod-like.

Shows rotation velocity follows a power-law with chain length.

Demonstrates super-diffusive long-time behavior in certain states.

Abstract

Structure and dynamics of an active polymer on a smooth cylindrical surface are studied by Brownian dynamics simulations. The effect of active force on the polymer adsorption behavior and the combined effect of chain mobility, length N, rigidity \k{appa}, and cylinder radius, R, on phase diagrams are systemically investigated. We find that complete adsorption is replaced by irregular alternative adsorption/desorption process at a large driving force. Three typical (spiral, helix-like, rod-like) conformations of the active polymer are observed, dependent on N, \k{appa}, and R. Dynamically, the polymer shows rotational motion in spiral state, snake-like motion in the intermediate state, and straight translational motion without turning back in the rod-like state. In the spiral state, we find that rotation velocity {\omega} and chain length follows a power-law relation {\omega}~N^(-0.42), consistent with the torque-balance theory of general Archimedean spirals. And the polymer shows super-diffusive behavior along the cylinder at long time in the helix-like and rod-like states. Our results highlight the mobility, rigidity, as well as curvature of surface can be used to regulate the polymer behavior.