A new chemical wave equation for ionic systems

In the best known example of chemical wave propagation, the Belusov–Zaikin–Zhabotinsky) reaction, most important species are ionic yet all theoretical studies that proport to describe wave porpagation in this media neglect the importance of charge neutrality coupling in ionic transport. In this paper we analyze the continuity and Poisson’s equations using the multiple time and length scale technique to emphasize the wide separation of scales between those of chemical wave propagation and the tendency toward electroneutrality. We derive a new equation for chemical waves in ionic systems and show that a coupling term due to the presence of a Planck liquid junction potential must be added to the neutral species equation to guarantee charge neutrality. It is pointed out that chemical waves in these systems are accompanied by propagating liquid junction potentials and that applied electric fields may significantly alter wave propagation, thus serving as a new experimental probe of chemical waves.