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Abstract

Experiments have shown that elasticity of disordered filamentous networks with compliant crosslinks is very
different from networks with rigid crosslinks. Here, we model and analyze filamentous networks as a collection
of randomly oriented rigid filaments connected to each other by flexible crosslinks that are modeled as wormlike
chains. For relatively large extensions we allow for enthalpic stretching of crosslink backbones. We show that
for sufficiently high crosslink density, the network linear elastic response is affine on the scale of the filaments’
length. The nonlinear regime can become highly nonaffine and is characterized by a divergence of the elastic
modulus at finite strain. In contrast to the prior predictions, we do not find an asymptotic regime in which the
differential elastic modulus scales linearly with the stress, although an approximate linear dependence can be
seen in a transition from entropic to enthalpic regimes. We discuss our results in light of recent experiments.