The dielectric and conductometric spectra of water-in-oil microemulsions below percolation in the frequency range from 1 MHz to 1.8 GHz have been analyzed on the basis of the electrical modulus formalism. In the frequency range investigated, this approach clearly evidences the presence of a particular polarization mechanism, resulting in a well-defined dielectric dispersion, located between that due to the orientational polarization of the bulk aqueous phase and that due to the ionic structure of the interface, usually occurring in heterogeneous systems. This polarization mechanism has been attributed to the "in-phase" correlation displacement of surfactant polar head groups surrounding each water droplet dispersed in the oil phase. This mechanism differs from the usual interfacial Maxwell-Wagner effect. The advantage of the electrical modulus formalism, in comparison with the analysis of the directly measured quantities, the permittivity ε′(ω), and the total electrical conductivity σ(ω), are briefly discussed. (c) 2001 Academic Press.

Occurrence of an intermediate relaxation process in water-in-oil microemulsions below percolation: The electrical modulus formalism / Bordi, Federico; Cametti, Cesare. - In: JOURNAL OF COLLOID AND INTERFACE SCIENCE. - ISSN 0021-9797. - 237:2(2001), pp. 224-229. [10.1006/jcis.2001.7456]

Occurrence of an intermediate relaxation process in water-in-oil microemulsions below percolation: The electrical modulus formalism

BORDI, FEDERICO;CAMETTI, Cesare
2001

Abstract

The dielectric and conductometric spectra of water-in-oil microemulsions below percolation in the frequency range from 1 MHz to 1.8 GHz have been analyzed on the basis of the electrical modulus formalism. In the frequency range investigated, this approach clearly evidences the presence of a particular polarization mechanism, resulting in a well-defined dielectric dispersion, located between that due to the orientational polarization of the bulk aqueous phase and that due to the ionic structure of the interface, usually occurring in heterogeneous systems. This polarization mechanism has been attributed to the "in-phase" correlation displacement of surfactant polar head groups surrounding each water droplet dispersed in the oil phase. This mechanism differs from the usual interfacial Maxwell-Wagner effect. The advantage of the electrical modulus formalism, in comparison with the analysis of the directly measured quantities, the permittivity ε′(ω), and the total electrical conductivity σ(ω), are briefly discussed. (c) 2001 Academic Press.
2001
dielectric dispersion; electrical modulus; maxwell-wagner effect; microemulsion; water-in-oil
01 Pubblicazione su rivista::01a Articolo in rivista
Occurrence of an intermediate relaxation process in water-in-oil microemulsions below percolation: The electrical modulus formalism / Bordi, Federico; Cametti, Cesare. - In: JOURNAL OF COLLOID AND INTERFACE SCIENCE. - ISSN 0021-9797. - 237:2(2001), pp. 224-229. [10.1006/jcis.2001.7456]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11573/254288
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