ORIENTATION AND TWINS-SEPARATION IN A MICELLAR CUBIC-CRYSTAL UNDER OSCILLATING SHEAR

A series of experiments has been performed in order to analyze the she ar orientation effect on a micellar cubic phase using small-angle x-ra y-scattering techniques. In a Couette cell, an oscillating shear of st rain amplitude less than unity was applied to the crystal. Using a x-r ay synchrotron beam, the reciprocal planes perpendicular to the flow v elocity and velocity gradient, respectively, were probed. Length and a ngle correlations were well characterized in both planes and full sepa ration of twinned fee single crystals was evidenced in some cases, eac h of them being coherent at millimeter scale.