Entanglement, elasticity and viscous relaxation of actin solutions

TL;DR

This study examines the rheological properties of actin solutions, revealing how entanglement and polymer length influence viscosity, plateau modulus, and relaxation times, supported by experimental measurements and the tube model theory.

Contribution

It provides new experimental data on actin solution rheology and interprets the entanglement transition using the tube model for semiflexible polymers.

Findings

Plateau modulus scales with concentration as power 7/5.

Terminal relaxation time scales with polymer length as power 3/2.

Results support the tube model for semiflexible polymer entanglement.

Abstract

We have investigated the viscosity and the plateau modulus of actin solutions with a magnetically driven rotating disc rheometer. For entangled solutions we observed a scaling of the plateau modulus versus concentration with a power of 7/5. The measured terminal relaxation time increases with a power 3/2 as a function of polymer length. We interpret the entanglement transition and the scaling of the plateau modulus in terms of the tube model for semiflexible polymers.