SPIN-LATTICE RELAXATION OF (H2O)-H-2 AT AMPHIPHILE WATER INTERFACES AS SEEN BY NMR

A simple two-state model is proposed describing the mean spin-lattice relaxation time T-1 of (H2O)-H-2 at amphiphile/water interfaces. The d ependence of the relaxation times on hydration is fitted for (H2O)-H-2 /DOPC, (H2O)-H-2/POPC and (H2O)-H-2/C(12)E(4) samples. Estimations of effective binding energies of water are obtained from the model being in the range of known values determined by quantum chemical calculatio ns and sorption measurements. Therefore, spin-lattice relaxation time measurements on interface water may prove a tool for characterizing th e surface energy conditions in a variety of amphiphile/water systems.