Conductivity of an inverse lyotropic lamellar phase under shear flow.
We report conductivity measurements on solutions of closed compact monodisperse multilamellar vesicles (the so-called "onion texture") formed by shearing an inverse lyotropic lamellar L(alpha) phase. The conductivity measured in different directions as a function of the applied shear rate reveals a small anisotropy of the onion structure due to the existence of free oriented membranes. The results are analyzed in terms of a simple model that allows one to deduce the conductivity tensor of the L(alpha) phase itself and the proportion of free oriented membranes. The variation of these two parameters is measured along a dilution line and discussed. The high value of the conductivity perpendicular to the layers with respect to that of solvent suggests the existence of a mechanism of ionic transport through the insulating solvent.
Panizza
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CPMOH, Université Bordeaux-1, 351 cours de la Libération, 33400 Talence, France. ppanizza@cribx1.u-bordeaux.fr
Soubiran
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Coulon
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Roux
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