Temperature control of the Belousov-Zhabotinsky reaction using a thermoresponsive polymer

The Ru(bpy)(3)-catalyzed Belousov-Zhabotinsky reaction is well-known as a self-oscillating phenomenon. Photoirradiation has been employed to switch the self-oscillation on and off. Here, we report that the self-oscillation can be switched on and off by temperature and that the oscillation amplitude can be regulated by subtle changes of temperature. Self-oscillating polymers composed of ruthenium (4-vinyl-4'-methyl-2,2'-bipyridine)bis(2,2'-bipyridine)bis(hexafluorophosphate) [Ru(bpy)(3)], N-isopropylacrylamide, and acrylic acid were synthesized by radical polymerization. It was found that the oscillating phenomenon was precisely regulated by temperature. Increasing the acrylic acid content reduced the lower critical solution temperature. As a result, the oscillation behavior for the copolymer having a higher acrylic acid content was observed at a lower temperature. The temperature control region can be modified by the incorporated acrylic acid. In addition, the carboxylic acid will be useful for conjugation with other materials.