LAUSR

Significance Self-healing hydrogels are increasingly finding use in diverse applications, such as artificial biological tissues, soft machines, and biosensors. Understanding the physical principle that governs the swelling and shrinking kinetics of self-healing hydrogels is indispensable for their applications but quite limited. Here, we show that the shrinking and swelling kinetics of self-healing hydrogels could be intrinsically asymmetric. The swelling kinetics is governed by the permanently crosslinked network structure, whereas the shrinking kinetics is governed by structure frustration, formed due to large differences in the heat and solvent diffusions. This study provides a useful step toward elucidating the essential physics governing the swelling and shrinking of self-healing hydrogels upon temperature change.