posted on 2023-11-20, 14:42authored byZhi Sheng, Jie Ma, Zihang Shen, Shaoxing Qu, Zheng Jia
Living tissues, such as skeletal muscles, are capable
of remodeling
and self-growth in response to their mechanical environment. In contrast,
synthetic materials, once formed, have little ability to grow and
reconstruct. Recently, mechanoresponsive self-growing hydrogel, a
novel hydrogel that can grow under mechanical stresses, has been reported.
However, the chemomechanics underpinning the growth and strengthening
behaviors of mechanoresponsive self-growing hydrogels remains largely
unexplored. Here, we present a chemomechanical model for mechanoresponsive
self-growing hydrogels by developing and integrating theories of mechanoradical
generation due to chain rupture, chemical kinetics of polymerization,
and new network formation. The chemomechanical model is applied to
theoretically investigate the concentration of mechanoradical generated
by stretching hydrogels, the polymerization kinetics of monomers and
cross-linkers, and the strengthened mechanical behavior of self-growing
hydrogels due to new network formation. Finally, we employ the theory
to predict the stress–stretch responses of self-growing hydrogels
under repetitive loading–unloading and growth cycles in the
closed system. The results, especially the predicted ultimate stresses
of the hydrogel over cycles, agree well with experimental measurements
made by Matsuda et al. and can consistently explain the experimentally
observed mechanical behaviors of self-growing hydrogels.