Microscopic Viscosity of the Interior Water Pool in Dodecylammonium Propionate Reversed Micelles

Abstract 13C-Chemical shifts and spin lattice relaxation times have been determined for dodecylammonium propionate/water/benzene or CCl4 reversed micelles and for [13C]glycine cosolubilized therein. Data obtained have been discussed in terms of the mobility of glycine molecules being effectively isolated from the surfactant headgroups by water molecules. The determined relaxation times of [13C]glycine in glycerol-water mixtures correlated well with the macroscopic and microscopic viscosities of the reversed micellar solution. In a relatively small water pool, the apparent viscosity of water surrounding glycine in the micelle (microviscosity) was corresponding to that of 78% aqueous glycerol solution. Increasing the size of water pool resulted in decrased microviscosities.