Role of molecular damage in crack initiation mechanisms of tough elastomers

• 成果类型: Article
• 署名作者: Ju, Jianzhu; Sanoja, Gabriel E.; Cipelletti, Luca; Ciccotti, Matteo; Zhu, Bangguo; Narita, Tetsuharu; Hui, Chung Yuen; Creton, Costantino
• 署名单位: Sorbonne Universite; Centre National de la Recherche Scientifique (CNRS); CNRS - Institute of Chemistry (INC); Universite PSL; Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI); University of Texas System; University of Texas Austin; Universite de Montpellier; Centre National de la Recherche Scientifique (CNRS); Institut Universitaire de France; Cornell University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-13200
• DOI: 10.1073/pnas.2410515121
• 发表日期: 2024-11-05
• 关键词: delayed fracture; strength; MODEL

摘要

Tough soft materials such as multiple network elastomers (MNE) or filled elastomers are typically stretchable and include significant energy dissipation mechanisms that prevent or delay crack growth. Yet most studies and fracture models focus on steady- state propagation and damage is assumed to be decoupled from the local stress and strain fields near the crack tip. We report an in situ spatial- temporally resolved 3D measurement of molecular damage in mechanophore-labeled MNE just before a crack propagates. This technique, complemented by digital image correlation, allows us to compare the spatial distribution of both damage and deformation in single network (SN) elastomers and in MNE. Compared to SN, MNE have a wide-spread damage in front of the crack and, surprisingly, delocalize strain concentration. A continuum model, where damage distribution is fully coupled to the crack tip fields, is proposed to explain these results. Additional measurements of time-dependent molecular damage during fixed grips relaxation in the presence of a crack reveal that the less localized damage distribution delays fracture initiation. The observations and exploratory modeling reveal the dynamic fracture mechanism of MNE, providing guidance for rational design of high-performance tough elastomers.