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Updated: Jul 11, 2026

Automatic Detection of Highly Organized Theta Oscillations in the Murine EEG
Published on: March 10, 2017
Association, partition, and surface activity in biphasic systems displaying relaxation oscillations
Vincent Pradines1, Rawad Tadmouri, Dominique Lavabre
1Laboratoire des IMRCP, UMR au CNRS No 5623, Université Paul Sabatier, 118, route de Narbonne, F-31062 Toulouse Cedex, France.
Abstract:
Several biphasic systems giving rise to periodical Marangoni instability have been analyzed from the point of view of the physicochemical properties of the involved compounds. In each case, the compound at the origin of the oscillatory behavior has been identified: the reactant cetyltrimethylammonium bromide (CTAB) for the CTAB/picric acid (PH) system and the product of reaction dodecyl sulfate tetraalkylammonium (TAADS) for the sodium dodecyl sulfate/tetraalkylammonium bromide (SDS/TAAB) system. The properties of the latter system have been varied progressively by increasing the chain length of the tetraalkylammonium ion. Oscillations were observed whichever the direction of transfer (from water to dichloromethane and from dichloromethane to water). The comparison of the dynamic interfacial tension, recorded during transfer, to equilibrium measurements shows that the instability is favored when partition is highly in favor of the organic phase. The main criteria for the appearance of the instability are a high surface activity and a low interfacial adsorption.
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