Constitutive behaviors of tough physical hydrogels with dynamic metal-coordinated bonds. (June 2020)

• Record Type: Journal Article
• Authors: Lin, Ji; Zheng, Si Yu; Xiao, Rui; Yin, Jun; Wu, Zi Liang; Zheng, Qiang; Qian, Jin
• Is Part Of: Journal of the mechanics and physics of solids. Volume 139(2020)
• Publication Date: 2020-06
• Subjects: Tough hydrogel -- Constitutive model -- Rate-dependent fracture -- Mullins effect -- Self-healing -- Metal-coordinated bond; Mechanics, Applied -- Periodicals; Solids -- Periodicals; Mechanics -- Periodicals; Mécanique appliquée -- Périodiques; Solides -- Périodiques; Mechanics, Applied; Solids; Periodicals; 531.05
• DOI: 10.1016/j.jmps.2020.103935
• Languages: English
• ISSNs: 0022-5096

Abstract

Abstract: Metal-coordination mediated physical hydrogels exhibit high strength/toughness and intriguing mechanical behaviors with the pronounced rate-dependent viscoelasticity and loading-path dependent strain softening. Also, the stress of the reloaded gels increases with more waiting time, indicating a self-healing effect. This paper aims to develop a constitutive model to capture these complex mechanical behaviors of the metal-coordination mediated physical hydrogels. The theoretical framework incorporates two main physical mechanisms: the microscopic kinetic dissociation/association of cross-links and inelastic conformational changes of gel networks. The model predictions agree well with the experimental data of gel responses under different scenarios, which simultaneously capture the time-dependent stress response, relaxation, hysteresis, self-healing behavior, as well as ultimate failure. The present work can provide theoretical guidance and methodological support for the design and practical applications of tough hydrogels mediated by metal-coordinated bonds as load-bearing materials.