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Water–AOT–alkylbenzene microemulsions: Influence of alkyl chain length on structure and percolation behavior

Appel, M. and Spehr, T. and Wipf, R. and Stühn, B. :
Water–AOT–alkylbenzene microemulsions: Influence of alkyl chain length on structure and percolation behavior.
[Online-Edition: http://www.sciencedirect.com/science/article/pii/S0021979712...]
In: Journal of Colloid and Interface Science, 376 (1) pp. 140-145.
[Article] , (2012)

Official URL: http://www.sciencedirect.com/science/article/pii/S0021979712...

Abstract

We study the percolation behavior of the water-in-oil (w/o) droplet phase of AOT (sodium bis[2-ethylhexyl] sulfosuccinate)-based microemulsions with different alkylbenzenes (toluene, ethylbenzene, butylbenzene or octylbenzene) as oil phase. We use microemulsions of varying composition with molar water to surfactant ratios 0 ⩽ W ⩽ 50 and droplet (water plus surfactant) volume fractions 10% ⩽ ϕ ⩽ 50%. Using dielectric spectroscopy, a percolation transition is observed in w/o microemulsions with butylbenzene or octylbenzene. With increasing molecular weight of the alkylbenzene, the percolation temperature TP decreases. The structure of the microemulsions is determined by small angle X-ray scattering (SAXS). With increasing molar weight of the alkylbenzene, the stability range of the L2 droplet phase extends to higher W. The larger amount of solubilizable water can be related to variable oil penetration of the AOT monolayer, which affects the spontaneous curvature of the surfactant shell.

Item Type: Article
Erschienen: 2012
Creators: Appel, M. and Spehr, T. and Wipf, R. and Stühn, B.
Title: Water–AOT–alkylbenzene microemulsions: Influence of alkyl chain length on structure and percolation behavior
Language: English
Abstract:

We study the percolation behavior of the water-in-oil (w/o) droplet phase of AOT (sodium bis[2-ethylhexyl] sulfosuccinate)-based microemulsions with different alkylbenzenes (toluene, ethylbenzene, butylbenzene or octylbenzene) as oil phase. We use microemulsions of varying composition with molar water to surfactant ratios 0 ⩽ W ⩽ 50 and droplet (water plus surfactant) volume fractions 10% ⩽ ϕ ⩽ 50%. Using dielectric spectroscopy, a percolation transition is observed in w/o microemulsions with butylbenzene or octylbenzene. With increasing molecular weight of the alkylbenzene, the percolation temperature TP decreases. The structure of the microemulsions is determined by small angle X-ray scattering (SAXS). With increasing molar weight of the alkylbenzene, the stability range of the L2 droplet phase extends to higher W. The larger amount of solubilizable water can be related to variable oil penetration of the AOT monolayer, which affects the spontaneous curvature of the surfactant shell.

Journal or Publication Title: Journal of Colloid and Interface Science
Volume: 376
Number: 1
Publisher: ELSEVIER
Divisions: 05 Department of Physics > Institute for condensed matter physics > Experimental Condensed Matter Physics
05 Department of Physics > Institute for condensed matter physics
05 Department of Physics
Date Deposited: 16 Apr 2012 07:12
Official URL: http://www.sciencedirect.com/science/article/pii/S0021979712...
Identification Number: doi:10.1016/j.jcis.2012.02.062
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