Structural features and nonlinear rheology of self-assembled networks of cross-linked semiflexible polymers

TL;DR

This study uses simulations to explore how the structural features of cross-linked semiflexible polymer networks influence their nonlinear rheological properties, revealing how connectivity affects strain stiffening.

Contribution

It provides new insights into the relationship between network structure and nonlinear mechanical behavior in biomimetic semiflexible polymer networks.

Findings

Network connectivity depends on crosslinker availability.

Strain stiffening behavior varies with network structure.

Simulated results align with experimental data on actin gels.

Abstract

Disordered networks of semiflexible filaments are common support structures in biology. Familiar examples include fibrous matrices in blood clots, bacterial biofilms, and essential components of cells and tissues of plants, animals, and fungi. Despite the ubiquity of these networks in biomaterials, we have only a limited understanding of the relationship between their structural features and highly strain-sensitive mechanical properties. In this work, we perform simulations of three-dimensional networks produced by the irreversible formation of crosslinks between linker-decorated semiflexible filaments. We characterize the structure of networks formed by a simple diffusion-dependent assembly process and measure their associated steady-state rheological features at finite temperature over a range of applied prestrains that encompass the strain-stiffening transition. We quantify the dependence of network connectivity on crosslinker availability and detail the associated connectivity dependence of both linear elasticity and nonlinear strain stiffening behavior, drawing comparisons with prior experimental measurements of the crosslinker concentration-dependent elasticity of actin gels.