9 - Self-oscillating polymer gels as novel biomimetic materials

Abstract

Stimuli-responsive polymer gels and their application to smart soft materials have been widely studied. On the other hand, we developed a novel biomimetic gel with an autonomous self-oscillating function like a heart muscle, which was firstly reported in 1996 as a “self-oscillating gel.” The self-oscillating gels were designed by utilizing the oscillating reaction, called the Belousov–Zhabotinsky (BZ) reaction recognized as a chemical model of the TCA cycle in organisms. The gel is composed of a poly(N-isopropylacrylamide) network in which the metal catalyst for the BZ reaction is covalently bonded. In a closed solution containing the reactants other than the catalyst, the gel undergoes spontaneous cyclic swelling–deswelling changes without any on–off switching of external stimuli. Their potential applications include several kinds of functional material systems such as biomimetic soft actuators and autonomous mass transport systems. In this chapter, recent progress on the self-oscillating polymers and gels is summarized.