Waves In Belousov-Zhabotinsky Reaction Research Articles

Chemical waves in heterogeneous media.

Formation of precipitation patterns and wave propagation in excitable media have attracted considerable scientific interest in the context of nonlinear chemical kinetics because of a new approach to micro and nanofabrication, in addition to some biological aspects. All precipitation patterns share common morphological characteristics, namely the formed patterns are stationary and no dynamical patterns can be observed in these classical precipitation systems (e.g., Liesegang phenomenon). However, it has been recently shown that in several circumstances dynamic patterns (chemical waves) can exist in purely inorganic precipitation systems similar to the well-known and studied (excitable) waves in Belousov-Zhabotinsky reaction. In this study, we show how to fine-tune the pattern characteristics in precipitation systems, such as the wavelength and the pattern morphology by changing the concentrations of the reagents, and we demonstrate chemical waves on a moving 3D spherical precipitation layer. We show that such precipitation waves have anomalous transport property, specifically superdiffusive nature, and it can be controlled by the initial concentration of the inner electrolyte. Moreover, we present several precipitation systems in which chemical wave propagation inside a moving precipitation layer can emerge. This observation points out the generality and robustness of similar behavior in diffusion-precipitation systems.

Bromomalonic-acid-induced transition from trigger wave to big wave in the Belousov-Zhabotinsky reaction

The Marangoni effects on chemical waves in the ferroin-catalyzed Belousov-Zhabotinsky reaction were studied. The main purpose of the present study was to understand the mechanism of the big wave, an accelerative chemical wave involving surface-tension-driven fluid motions. Spatiotemporal variations of surface tension caused by a chemical wave were measured using the Wilhelmy method. The transition from conventional trigger waves to big waves, due to a concentration change of bromomalonic acid, was observed. The strong surface activity of the bromomalonic acid which was responsible for the transition was also observed. It led to an acceleration of the big waves through the Marangoni effect.