The origin of stiffening in cross-linked semiflexible networks

TL;DR

This paper investigates the mechanisms behind strain stiffening in protein networks, revealing that non-affine rearrangements drive the transition from bending to stretching responses, with thermal undulations playing a minor role.

Contribution

It introduces a finite strain analysis of a 2D network model, highlighting the primary role of non-affine rearrangements in stiffening, and clarifies the limited impact of thermal undulations.

Findings

Stiffening results from a transition from bending to stretching response.

Non-affine network rearrangements are the main cause of stiffening.

Thermal undulations only delay the stiffening transition.

Abstract

Strain stiffening of protein networks is explored by means of a finite strain analysis of a two-dimensional network model of cross-linked semiflexible filaments. The results show that stiffening is caused by non-affine network rearrangements that govern a transition from a bending dominated response at small strains to a stretching dominated response at large strains. Thermally-induced filament undulations only have a minor effect; they merely postpone the transition.