Issue 31, 2022

An extreme toughening mechanism for soft materials


Soft yet tough materials are ubiquitous in nature and everyday life. The ratio between fracture toughness and intrinsic fracture energy of a soft material defines its toughness enhancement. Soft materials’ toughness enhancement has been long attributed to their bulk stress-stretch hysteresis induced by dissipation mechanisms such as Mullins effect and viscoelasticity. With a combination of experiments and theory, here we show that the bulk dissipation mechanisms significantly underestimate the toughness enhancement of soft tough materials. We propose a new mechanism and scaling law to account for extreme toughening of diverse soft materials. We show that the toughness enhancement of soft materials relies on both bulk hysteretic dissipation, and near-crack dissipation due to mechanisms such as polymer-chain entanglement. Unlike the bulk hysteretic dissipation, the near-crack dissipation does not necessarily induce large stress-stretch hysteresis of the bulk material. The extreme toughening mechanism can be potentially universally applied to various soft tough materials, ranging from double-network hydrogels, interpenetrating-network hydrogels, entangled-network hydrogels and slide-ring hydrogels, to unfilled and filled rubbers.

Graphical abstract: An extreme toughening mechanism for soft materials

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Article information

Article type
10 May 2022
27 Jun 2022
First published
27 Jun 2022
This article is Open Access
Creative Commons BY license

Soft Matter, 2022,18, 5742-5749

An extreme toughening mechanism for soft materials

S. Lin, C. D. Londono, D. Zheng and X. Zhao, Soft Matter, 2022, 18, 5742 DOI: 10.1039/D2SM00609J

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