Force-facilitated rare thermally activated bond rupture enables stress relaxation and hysteresis in hydrogel elastomers
Journal
Extreme Mechanics Letters
Journal Volume
83
Start Page
102443
ISSN
23524316
Date Issued
2026-03
Author(s)
Abstract
Hydrogel elastomers display stress relaxation, hysteresis, and the Mullins effect even in highly crosslinked networks where chain mobility is strongly suppressed, yet their microscopic origin remains elusive. Although bond rupture has been recognized as a possible contributor, its temporal and spatial occurrence under applied force has not been clearly elucidated. Dissipative particle dynamics simulations with bond-rupture capability reproduce the macroscopic responses, attributed to rare rupture events in tensile strands. Rupture does not result from direct mechanical fracture but from thermal fluctuations that surpass a stress-lowered energy barrier, initiating network reconfiguration that relaxes stress and produces hysteresis. Microscopic variations in mean bond length quantitatively mirror macroscopic stress evolution, ruling out viscoelastic dissipation as the primary mechanism. Our results establish thermally activated bond rupture as the unifying microscopic origin of stress relaxation and hysteresis in hydrogel elastomers, linking microscopic bond dynamics to macroscopic stress responses under cyclic deformations.
Subjects
Bond rupture
Elastomer
Hydrogel
Hysteresis
Stress relaxation
Thermally activated
Publisher
Elsevier Ltd
Type
journal article