Belousov-Zhabotinsky Reaction in Protic Ionic Liquids

摘要

Rhythmic oscillation is one of the universal phenomena in living systems, and important rhythms that sustain a life, such as heart beating, breathing, and circadian rhythm, occur at all levels in physiological tissue. The Belousov-Zhabotinsky (BZ) reaction is an oscillating reaction accompanying a rhythmical oscillation of the redox potential of metal catalysts, such as ferroin and ruthenium bipyridine, Ru(bpy)3. Typically, the BZ reaction is caused in a strong acidic aqueous solution using sulfuric acid or HNO3 as proton source with an oxidant (for example, sodium bromate, NaBrO3) and an organic acid acting as the reductant (for example, malonic acid, MA, or citric acid). The rhythmic self-oscillation of the BZ reaction is known to have many analogies to living systems and is important from the perspective of understanding nonlinear, non-equilibrium science.Furthermore, as the first research group, which converted the chemical oscillation of a BZ reaction into a mechanical change in polymer gels, we have been systematically studying a "self-oscillating gel" that exhibits an autonomous swelling-deswelling oscillation under nonoscillatory outer conditions. However, to apply this gel to functional materials, there are two problems that have to be solved: 1) the BZ reaction occurs only under strong acidic conditions (a typically pH value is below one) and 2) the duration of the operation is short.