Controlled recombination rate of lophyl radicals in cationic surfactant micelles

Abstract

In this study, we aimed to control the recombination rate of lophyl radicals in micelles, which were produced from a lophine dimer by ultraviolet irradiation, formed by cationic surfactants with different alkyl chain lengths. The recombination rate in the micellar solution of the surfactant with a shorter alkyl chain was enhanced compared to that with a longer alkyl chain. Small-angle neutron scattering measurements showed that mixtures of the cationic surfactant and the lophine dimer derivative formed elliptical micelles, and a smaller inner volume was observed when shorter chain surfactants were used. Furthermore, evaluation of the kinetic parameters indicated that the randomness of the lophyl radical in the shorter surfactant micelle was higher than that in the longer surfactant micelle. These results revealed that the size of the confined space formed by the micelles determines the recombination rate of the lophyl radicals. This provides a new methodology for the development of volatile and nonvolatile molecular memories with arbitrary retention times and future quantum computing based on photochromic compounds.