On the birefringence of water-alkane-AOT microemulsions

Citation
Jc. Fernandez et al., On the birefringence of water-alkane-AOT microemulsions, COLL SURF A, 157(1-3), 1999, pp. 35-46
Citations number
14
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
ISSN journal
09277757 → ACNP
Volume
157
Issue
1-3
Year of publication
1999
Pages
35 - 46
Database
ISI
SICI code
0927-7757(19991030)157:1-3<35:OTBOWM>2.0.ZU;2-S
Abstract
For some years, several authors have tried to explain the behavior of elect ric field induced birefringence in some microemulsion systems. In this work we continue a line based on works by van der Linden [S. Geiger, E. van der Linden, D. Bedeaux, Physica A 156(1989) 130, C. Roman Vas, G.J.M. Koper, E . van der Linden, J. Phys. II(France) 4 (1994) 163] and others, using a mat hematical description derived from first principles without approximations. Previous work assumes that the AOT layer width is small compared with the radius of the core, and that the static permittivity of the core-water in w ater in oil (W/O) microemulsion is practically infinite. These assumptions are questionable for small droplets where negative birefringence is observe d, and also for O/W microemulsions. Our model sets no restriction on the la yer width or the core static permittivity, yielding general analytical equa tions for the calculation of the Kerr constant. Nevertheless, for two exper imental systems, our conclusions are essentially in agreement with these au thors, while discrepancies in the numerical values of the relevant paramete rs have been observed. Namely, larger values for the rigidity elastic const ant have been found, results compatible with previous theoretical predictio ns arising from general principles and experimental works. (C) 1999 Elsevie r Science B.V. All rights reserved.