Tehrani Mohammad, Ghalamzan Zahra, Sarvestani Alireza
Department of Mechanical Engineering, Ohio University, Athens, OH 45701, United States of America.
Phys Biol. 2018 Jun 25;15(6):066002. doi: 10.1088/1478-3975/aac5a8.
The classical theory of polymer elasticity is built upon the assumption of network monodispersity-the premise that polymer networks are comprised of sub-chains of equal length. The crosslinking of biopolymers, however, is a random process and the resultant networks are likely to be polydisperse. The effect of structural polydispersity on the mechanical behavior of biopolymer networks is not well understood. The purpose of this contribution is to show how network polydispersity controls mechanical behavior and the ultimate properties of crosslinked semi-flexible filaments at finite deformations. The proposed micromechanical continuum model is based on the force-elongation relation of individual chains of different lengths. It is shown that the mechanical strength of the network is controlled by the finite-extensibility of filaments and the degradation of shorter filaments at relatively small stretches. The progressive failure of filaments continues and eventually determines the ultimate strength of the network. The predicted stress-stretch behaviors are in reasonable agreement with the experimental data for connective tissues.
聚合物弹性的经典理论是基于网络单分散性的假设——即聚合物网络由等长的子链组成这一前提。然而，生物聚合物的交联是一个随机过程，所形成的网络很可能是多分散的。结构多分散性对生物聚合物网络力学行为的影响尚未得到很好的理解。本文的目的是展示网络多分散性如何在有限变形下控制交联半柔性细丝的力学行为和最终性能。所提出的微观力学连续介质模型基于不同长度的单个链的力-伸长关系。结果表明，网络的机械强度由细丝的有限伸长性以及较短细丝在相对较小拉伸下的降解所控制。细丝的渐进性破坏会持续并最终决定网络的极限强度。预测的应力-拉伸行为与结缔组织的实验数据合理吻合。
