ELECTROCONVECTION AND PATTERN-FORMATION IN A SUSPENDED SMECTIC FILM

We have observed convective flow in a thin freely suspended film of smectic-A liquid crystal when a sufficiently large electric field is applied in the plane of the film. The convective flow neither reorients the director nor deforms the free surfaces of the film. Thus the film behaves as a two-dimensional isotropic fluid. We have studied the onset of this flow in two film holders, one which allows injection of charges from the electrodes into the film and one which does not. We present measurements of the threshold voltage and of the wavelength of the vortex pattern as a function of the frequency of the applied field, and briefly discuss the nature of the mechanisms driving the flow. © 1990 The American Physical Society.