1H and 13C longitudinal and transverse relaxation in aerosol OT in methanol solution and inverted microemulsions in benzene

Abstract

1 H and 13C longitudinal and transverse relaxation in inverted microemulsions of Aerosol OT (AOT) in deuterated benzene has been studied as a function of composition and resonance frequency. Except at high AOT concentrations (> 2 mol AOT per kg C6D6) and low water content [AOT/H2O mole ratio (R) < 2] the frequency dependence of T1, T2 and the nuclear Overhauser effects can be satisfactorily interpreted in terms of the two-step correlation function of Wennerstrom et al. (H. Wennerstrom, B. Lindman,O. Soderman, T. Drakenberg and J. B Rosenholm, J. Am. Chem. Soc., 1979, 101, 6860). The solw correlation time decreases as the water content increases up to R≈ 3 and thereafter is constant. This behaviour suggests that the slow process is loss of AOT from the aggregate into the hydrocarbon phase. Relaxation of AOT in dilute methanol solution has been used to determine the relaxation mechanism.