Turing Pattern Formation by the CIMA Reaction in a Chemical System Consisting of Quaternary Alkyl Ammonium Cationic Groups

For the spontaneous generation of a Turing pattern, two intermediate species, an activator and an inhibitor, should be generated with the diffusion coefficient of the activator smaller than that of the inhibitor. The chlorite-iodide-malonic acid (CIMA) reaction that generates the activator, I(-), and inhibitor, ClO(2-), was performed in an open gel reactor. In order to lower the effective diffusivity of I(-), micelles of quaternary alkyl ammonium cationic amphiphiles and polymers having a quaternary alkyl ammonium cationic side chain were combined in the CIMA reaction system in an open gel reactor. A Turing pattern formation was observed with the addition of n-dodecyltrimethylammonium bromide. Employing the gel reactor prepared by the polymerization of a monomer having quaternary alkyl ammonium cationic side chains also leads to the generation of a Turing pattern. The micelles and polymers are believed to trap I(-) in their vicinity as a counterion to lower the effective diffusivity.