The Role of Architecture in the Elastic Response of Semiflexible Polymer and Fiber Networks

TL;DR

This paper investigates how the architecture of thermally fluctuating semiflexible polymer networks influences their elastic response, revealing a strong dependence on network structure and polymer length, with implications for understanding biological and synthetic materials.

Contribution

It introduces a comprehensive analysis of the elastic behavior of thermal polymer networks, emphasizing the impact of architecture and polymer length, which was previously underexplored.

Findings

Elastic response is highly sensitive to network architecture.

Polymer length significantly influences macroscopic elasticity.

Thermal fluctuations cause qualitative differences from athermal models.

Abstract

We study the elasticity of cross-linked networks of thermally fluctuating stiff polymers. As compared to their purely mechanical counterparts, it is shown that these thermal networks have a qualitatively different elastic response. By accounting for the entropic origin of the single-polymer elasticity, the networks acquire a strong susceptibility to polydispersity and structural randomness that is completely absent in athermal models. In extensive numerical studies we systematically vary the architecture of the networks and identify a wealth of phenomena that clearly show the strong dependence of the emergent macroscopic moduli on the underlying mesoscopic network structure. In particular, we highlight the importance of the full polymer length that to a large extent controls the elastic response of the network, surprisingly, even in parameter regions where it does not enter the macroscopic moduli explicitly. We provide theoretical scaling arguments to relate the observed macroscopic elasticity to the physical mechanisms on the microscopic and the mesoscopic scale.