A defect mediated lamellar to isotropic transition of amphiphile bilayers

Antara Pal; Georg Pabst; V. A. Raghunathan

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arXiv · 1111.5902

A defect mediated lamellar to isotropic transition of amphiphile bilayers

Antara Pal·Georg Pabst·V. A. Raghunathan

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Abstract

We report the observation of a novel isotropic phase of amphiphile bilayers in a mixed system consisting of the ionic surfactant, sodium docecylsulphate (SDS), and the organic salt p-toludine hydrochloride (PTHC). This system forms a collapsed lamellar ($L_\alpha$) phase over a wide range of water content, which transforms into an isotropic phase on heating. This transition is not observed in samples without excess water, where the $L_\alpha$ phase is stable at higher temperatures. Our observations indicate that the $L_\alpha$ - isotropic transition is driven by the unbinding of edge dislocation loops and that the isotropic phase in the present attraction-dominated system is the analogue of the sponge phase usually seen in amphiphile systems dominated by interbilayer steric repulsion.

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Antara Pal, Georg Pabst, V. A. Raghunathan. 2011-11-25. A defect mediated lamellar to isotropic transition of amphiphile bilayers. https://arxiv.org/abs/1111.5902

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