Spectral simulation study of the positional exchange of a spin probe in an aerosol OT reversed micelle

Abstract

The ESR spectra of a spin probe, 2,2,6,6-tetramethyl-4-piperidone N-oxide, in degassed Aerosol OT reversed micelle in heptane solution were examined using computer simulation on the sample in which the molar ratio of water to surfactant was 31. For such largely water-containing micelles, each line of the hyperfine structure split into a doublet at low temperatures as a result of the spin probe locating in the water pool and in the shell formed by the surfactant molecules. From the simulation of the high-field line, the exchange rates between these positions and the fractions in each were obtained as a function of temperature. A two phase model of the water pool was proposed in order to fit the calculated to the observed spectra.