Rheology of Active Filament Solutions

TL;DR

This paper investigates how active biofilament solutions exhibit unique viscoelastic behaviors due to motor proteins, with a focus on differences across phase transitions and the effects of contractile activity.

Contribution

It derives constitutive equations for stress in active filament solutions, revealing how activity influences viscoelastic properties across different phases.

Findings

Contractile activity causes significant differences in viscoelasticity.

Stress relaxation varies across isotropic and ordered phases.

Active solutions show distinct behaviors compared to passive systems.

Abstract

We study the viscoelasticity of an active solution of polar biofilaments and motor proteins. Using a molecular model, we derive the constitutive equations for the stress tensor in the isotropic phase and in phases with liquid crystalline order. The stress relaxation in the various phases is discussed. Contractile activity is responsible for a spectacular difference in the viscoelastic properties on opposite sides of the order-disorder transition.