A micromechanics-based model for visco-super-elastic hydrogel-based nanocomposites

• Published in: International journal of plasticity Vol. 144; p. 103042
• Main Authors: Saadedine, Mahrez, Zaïri, Fahmi, Ouali, Nourdine, Tamoud, Abderrahman, Mesbah, Amar
• Format: Journal Article
• Language: English
• Published: New York Elsevier Ltd 01.09.2021; Elsevier BV; Elsevier
• Subjects: Biaxial loads; Engineering Sciences; Extreme stretchability; History-dependent effects; Hydrogel-based nanocomposites; Hydrogels; Hysteresis; Load history; Micromechanical modeling; Micromechanics; Nanocomposites; Nanoparticles; Room temperature; Self-healing; Strain rate; Stretchability; Hydrogel-based nanocomposites; Self-healing; History-dependent effects; Extreme stretchability; Micromechanical modeling
• ISSN: 0749-6419; 1879-2154
• DOI: 10.1016/j.ijplas.2021.103042

•We assess the visco-super-elastic mechanics of hydrogels.•We propose a model connecting nanostructure, chains dynamics and overall mechanics.•We describe the mechanisms of nanoparticles reinforcement and failure.•We predict the room temperature self-healing facility in connection to nanostructure. This article presents a micromechanics-based model that constitutively relates internal network physics of hydrogel-based nanocomposites with their visco-super-elastic mechanics. The model is based on the Eshelby inclusion theory combined to the concept of cubic material volume to take into account the effective role of inorganic nanoparticles on the finite-strain response of hydrogels. Dynamic bonds between hydrogel chains and nanoparticles allow to describe the impressive time-dependent properties of hydrogel-based nanocomposites such as rate-dependent extreme stretchability, strong hysteresis upon stretching-retraction and room temperature self-healing facility. The model is compared to a few available experimental data of a variety of hydrogel-nanofiller material systems in terms of stress-strain response till failure, hysteresis, continuous relaxation and self-healing. The effects on the hydrogel behavior of loading conditions (strain rate and strain level) and internal network structures (due to variations in reinforcing elements and cross-linker amounts) are examined. The micromechanical model simulations are found in excellent agreement with experimental observations showing the relevance of the proposed approach. The mechanisms of nanofillers reinforcement and failure are discussed with respect to the model. The room temperature self-healing characteristics of hydrogel systems are discussed in connection to loading history and nanostructure. To further illustrate the model capabilities, the behavior of hydrogel systems is finally treated under different biaxial loading conditions.