A Multiaxial Theory of Double Network Hydrogels

Abstract

The incorporation of a stiff and brittle phase into a soft and flexible polymer network makes double network hydrogels remarkably tougher than the conventional one. It also induces a stress softening in cyclic loading, which is seemingly identical to that of filled rubbers. Therefore, material models proposed for double network hydrogel are mostly based on continuum damage theories of filled elastomers. However, recent experimental studies clearly distinguish double network hydrogels from filled elastomers by the damage cross-effect in multiaxial deformation. In this paper, a micromechanical model for double network hydrogels under multiaxial deformation is proposed on the basis of the analytical network-averaging concept. Accordingly, the directional fracture of the first network results from cumulative damage in all directions. Furthermore, the strong interpenetration of the two networks is taken into account. The proposed analytical model includes very few physically motivated material constants and demonstrates excellent agreement with comprehensive experimental data of double network hydrogels under multiaxial loading conditions.

Thermodynamics of strain-induced crystallization in filled natural rubber under uni- and biaxial loadings, Part II: Physically-based constitutive theory

“…Dargazany et al (2014a,b); Plagge and Klüppel (2018); Plagge and Hentschke (2021); Gros et al (2019b) modeled strain-induced crystallization by rate-independent damage evolutions, which are subjected to the same issues as elastoplasticity models. Furthermore, since damage-elastoplastic models are rate-independent, they cannot capture time-dependent strain-induced crystallization (Khiêm et al, 2019).…”

Fast-Recoverable, Self-Healable, and Adhesive Nanocomposite Hydrogel Consisting of Hybrid Nanoparticles for Ultrasensitive Strain and Pressure Sensing

“…In recent years, various strategies have been proposed to fabricate multifunctional hydrogels with the desirable properties as mentioned above. Among them, the most utilized method is introducing the dynamic physical bonds − ,− and chemical bonds ,− into the macromolecular networks together. The reversibility of the dynamic physical bonds endows hydrogels with self-healing capability, whereas the chemical bonds play the role in enhancing their mechanical performance.…”

Fabrication of Multiresponsive Magnetic Nanocomposite Double‐Network Hydrogels for Controlled Release Applications

“…In general, the double‐network hydrogels (DN hydrogels) are composed of two interpenetrating polymer networks. [ 73–76 ] The first network can act as a “sacrificial bond” to dissipate a large amount of energy when subjected to external forces, and the other network acts as a “hidden length” after the first network is broken to maintain the basic viscoelasticity of the hydrogel. [ 74,77–79 ] Therefore, the emerging ncDN hydrogels with magnetic materials not only maintain the responsiveness of the NC hydrogels but also possess excellent mechanical strength which is contributed from the double network.…”