Delayed Mechanical Response to Chemical Kinetics in Self-Oscillating Hydrogels Driven by the Belousov–Zhabotinsky Reaction

We show experimentally that chemical and mechanical self-oscillations in Belousov–Zhabotinsky hydrogels are inherently asynchronous, is, there is a detectable delay swelling–deswelling response after change the redox state. This phenomenon observable many previous experimental studies potentially has far-reaching implications for functionality time of material future applications; however, so far, it not been quantified or reported systematically. Here, we provide comprehensive qualitative quantitative description chemical-to-mechanical delay, propose to explain as consequence slow nonequilibrium dynamics polymer material. Specifically, standard hydrogel pieces large enough transport processes, example, counterion migration water diffusion, cannot occur instantaneously throughout entire gel piece, opposed theoretical considerations. As result, volume may be governed by characteristic time, which leads emergence oscillation. supported our calculations.