Abstract
A reverse microemulsion composed of octane, water and the surfactant aerosol OT (AOT) consists of nanometer-sized droplets of water surrounded by a monolayer of AOT molecules floating in a sea of oil. If one adds to this system the components of the Belousov-Zhabotinsky (BZ) oscillating chemical reaction, one can observe a remarkable variety of complex patterns. These include spirals and traveling concentric circular waves that may move either toward or away from their centers, segmented traveling waves, chaotic waves, stationary Turing patterns and standing waves, and localized patterns. The wavelengths of the observed structures are typically of the order of 200 µm, i.e., about 20,000 droplet diameters. The type of pattern obtained can be controlled by varying the microemulsion composition, which determines the size and spacing of the droplets, and the concentrations of the BZ reactants, which determines the chemical kinetics. The behavior can be simulated numerically using relatively simple reaction-diffusion models.