Volumetric, transport and ultrasonic properties of the water/aot/n-heptane microemulsions

Donato, I. D. and Goffredi, F. and Turco Liveri, V. and Vassallo, G. (1991) Volumetric, transport and ultrasonic properties of the water/aot/n-heptane microemulsions. Accademia Peloritana dei Pericolanti Classe FF.MM.NN., 69. pp. 47-69.

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Abstract

Density, sound velocity, viscosity and ultrasonic absorption measurements in water/AOT/$n$-heptane $(w/o)$ microemulsions as a function of temeperature and of the molar ratio water/AOT $(R)$ have been performed. The density and the adiabatic compressibility of the micellar phase indicate that, by increasing temperature, the micelles become more expansible and less compressible. The viscosity trend, explained in terms of intermicellar interactions, evidences that, by increasing $R$, the parallel increase of the hydration of the polar head of AOT leads to more charged micelles. Percolation was observed only near the upper critical temperature $(Tc^u)$ whereas a regular behavior was observed near the lower critical temperatures. The divergence of the viscosity near $Tc^u$ is accounted for a mass and charge xchange mechanism enhanced by a Grotthus-like effect. Finally, the ultrasonic absorptions show a relaxation process occiirring at 10 MHz independent from both $T$ and $R$ which can be ascribed to a conformational change involving the head group of the AOT molecule.

Item Type:	Article
Subjects:	M.U.S. - Miscellanea > Atti Accademia Peloritana > Classe di Scienze Fisiche, Matematiche e Naturali > 1991 > Supplemento 1 M.U.S. - Miscellanea > Atti Accademia Peloritana > Classe di Scienze Giuridiche, Economiche e Politiche > 1991 > Supplemento 1 M.U.S. - Miscellanea > Atti Accademia Peloritana > Classe di Lettere Filosofia e belle Arti > 1991 > Supplemento 1
Depositing User:	Dr M P
Date Deposited:	01 Oct 2012 09:47
Last Modified:	03 Apr 2013 10:43
URI:	http://cab.unime.it/mus/id/eprint/810

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