返回
Modeling spider silk supercontraction as a hydration-driven solid-solid phase transition
DOI:10.1016/j.jmps.2024.105959.png)
摘要
En 中文
Spider silks have attracted significant interest due to their exceptional mechanical properties, which include a unique combination of high strength, ultimate strain, and toughness. A notable characteristic of spider silk, still debated from both mechanical and functional viewpoints, is supercontraction -a pronounced contraction of up to half its original length when an unconstrained silk thread is exposed to a wet environment. We propose a predictive model for the hygro-thermo-mechanical behavior of spider silks, conceptualizing this phenomenon as a solid-solid phase transition, similar to the glass transition in rubber, but driven by humidity. As wetting increases, the system undergoes a transition, at the network scale, from a hard, dry state -where the material behavior is governed by stiff chains elongated along the fiber axis- to a soft, wet state, regulated by a rubber-like response. We model these states using a two-well free energy function dependent on molecular stretch, with transition energy modulated by humidity. Based on the methods of Statistical Mechanics, we deduce that supercontraction can be interpreted as a solid-solid phase transition. We elucidate the important role of thermal fluctuations. In particular, the decrease of the critical humidity needed for supercontraction as temperature grows results as an effect of entropic stabilization of the softer rubbery phase. Our model quantitatively predicts the observed experimental behavior, capturing the temperature dependence of humidity-induced supercontraction effects and related cooperative properties.
Keyword:
Phase transition
Statistical mechanics
Spider silk
Humidity
Supercontraction
AI总结
对已上传原文的论文进行重点信息的提取,主要内容包括:简要概述、研究摘要、背景介绍、关键亮点、图文解析、展望与总结。
期刊
IF:
6
论文数:
5.3K
被引数:
3.0W

