A pulsed field gradient (FTH)-H-1 NMR study on the system soybean lecithin/water/perdeuterated cyclohexane, covering a wide range of compositions, is presented. The water diffusion was found to be Gaussian with a well-defined, time-independent, single diffusion coefficient. After the contribution from the diffusion of water dissolved in the cyclohexane has been properly taken into account, all the data follow the same master curve as a function of the water to lecithin molar ratio (W-0) The dominating mechanism for the water diffusion was found to be the motion inside giant wormlike reverse aggregates mediated by an interaggregates exchange with a characteristic time on the order of microseconds. For all the lecithin concentrations investigated, increasing the value of W-0 increases the water diffusion up to W-0 = 15, where a structural transition toward spherical aggregates causes a decrease in the water diffusion.

Water diffusion in polymer-like reverse micelles II: composition dependence

PALAZZO, Gerardo;
1999-01-01

Abstract

A pulsed field gradient (FTH)-H-1 NMR study on the system soybean lecithin/water/perdeuterated cyclohexane, covering a wide range of compositions, is presented. The water diffusion was found to be Gaussian with a well-defined, time-independent, single diffusion coefficient. After the contribution from the diffusion of water dissolved in the cyclohexane has been properly taken into account, all the data follow the same master curve as a function of the water to lecithin molar ratio (W-0) The dominating mechanism for the water diffusion was found to be the motion inside giant wormlike reverse aggregates mediated by an interaggregates exchange with a characteristic time on the order of microseconds. For all the lecithin concentrations investigated, increasing the value of W-0 increases the water diffusion up to W-0 = 15, where a structural transition toward spherical aggregates causes a decrease in the water diffusion.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11586/38555
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