Dynamic fracture and catastrophic crack branching in highly entangled hydrogels

IF 9.5 1区综合性期刊 Q1 MULTIDISCIPLINARY SCIENCES

Proceedings of the National Academy of Sciences of the United States of America Pub Date : 2026-09-17 DOI:10.1073/pnas.2603322123

Hang Yang, Shuming Kang, Yujing Du, David A. Weitz, Joost J. Vlassak

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引用次数: 0

Abstract

Despite extensive research on advanced soft materials, how fracture resistance evolves under dynamic loading and how cracks propagate remain incompletely understood. Here we show that dynamic fracture in long-chain, highly entangled polymer hydrogel networks with near-perfect elasticity is governed by localized viscous dissipation at the crack tip. Using highly entangled gels as a model system, we systematically vary network and loading parameters to evaluate the effects of loading rate, network topology, and solvent viscosity on fracture behavior. We find that, due to viscoelastic dissipation, the dynamic fracture toughness can be significantly lower than the quasi-static fracture toughness. Cracks can propagate at velocities approaching the shear-wave speed and undergo pronounced, unconventional branching. We develop a shear-lag model to describe the dissipation mechanism. The model predicts that the fracture energy scales inversely with a Weissenberg-like number ( W ) that combines strain rate, chain length, mesh size, and solvent viscosity, and it recovers the Lake–Thomas limit at low values of W . These results reveal how localized viscous dissipation governs fracture in highly elastic, entangled hydrogels and provide design principles for improving failure resistance in soft materials and devices operating under dynamic loading.

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高缠结水凝胶中的动态断裂和突变裂纹分支

尽管对先进软质材料进行了广泛的研究，但在动载荷作用下，其抗断裂性能是如何演变的，以及裂纹是如何扩展的，人们仍然不完全了解。本研究表明，在弹性接近完美的长链、高度纠缠的聚合物水凝胶网络中，动态断裂是由裂纹尖端的局部粘性耗散控制的。我们以高度纠缠的凝胶为模型系统，系统地改变网络和加载参数，以评估加载速率、网络拓扑结构和溶剂粘度对断裂行为的影响。我们发现，由于粘弹性耗散，动态断裂韧性可以明显低于准静态断裂韧性。裂缝可以以接近横波速度的速度传播，并经历明显的、非常规的分支。我们建立了一个剪切滞后模型来描述耗散机制。该模型预测，断裂能与结合应变速率、链长、网格尺寸和溶剂粘度的Weissenberg-like数(W)成反比，并在W值较低时恢复Lake-Thomas极限。这些结果揭示了局部粘性耗散如何控制高弹性纠缠水凝胶的断裂，并为提高软材料和设备在动载荷下的抗破坏能力提供了设计原则。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Proceedings of the National Academy of Sciences of the United States of America 综合性期刊-综合性期刊

CiteScore

19.00

自引率

0.90%

发文量

3575

审稿时长

2.5 months

期刊介绍： The Proceedings of the National Academy of Sciences (PNAS), a peer-reviewed journal of the National Academy of Sciences (NAS), serves as an authoritative source for high-impact, original research across the biological, physical, and social sciences. With a global scope, the journal welcomes submissions from researchers worldwide, making it an inclusive platform for advancing scientific knowledge.