Control of spontaneous spiral formation in a zwitterionic micellar medium

The transition from planar fronts, trigger waves or solitary pulses to spirals in excitable media, hasattracted increasing interest in the past few decades, mainly because of its relevance for biological andmedical applications. In this paper we describe a new and convenient method for spiral generationstarting from symmetric wavefronts. By using the micelle-forming zwitterionic surfactant N-tetradecyl-N,N-dimethylamine oxide in a Belousov–Zhabotinsky solution, it is possible to control to a large extentthe domains where spirals can be spontaneously generated. The mechanism responsible for thewavefront break up lies in the interaction of the propagating waves with the unexcitable regions formedby the interaction of the surfactant with some of the Belousov–Zhabotinsky key intermediates.