Self-Propulsion Mode Switching of a Briggs–Rauscher Droplet

Autocatalysis induces nonlinearity in chemical and/or biological systems, and is important for understanding the emergence of life in nature. To enhance the autonomy of self-propulsion in an open system, we introduced a Briggs–Rauscher (BR) reaction into self-propelled droplet systems. In this study, a droplet composed of a BR solution in an oil phase containing a monoolein surfactant exhibited various types of motion, that is, continuous, oscillatory, and no motions of the droplet. The motions observed depended on the concentrations of potassium iodate and hydrogen peroxide in the BR solution. These results indicated that the driving force in this system was generated by the reaction between monoolein and one of the intermediates of the BR reaction, iodine. Our system can contribute to the establishment of a novel biomimetic object in which the autocatalytic process acts as a key factor for inducing various types of motion.