Dynamic processes in the liquid crystal-water emulsion under shear flow and electric field

Abstract

We present the results of experimental investigation of dynamical processes arising in liquid crystal-water emulsion under action of a decay shear flow and ac electric field. The 10 : 1 emulsion, consisting of the well-studied nematic mixture E7 and ionized water was prepared by usage of ultrasonic (29 kHz) mixer. It made possible to get a number of water droplets with the distribution of diameters in the range 2… 20μm. So, the slow decreasing of sizes of these instabilities resulted in corresponding slow motion of the attracted water droplets. The strong electric filled, which stabilized the initial homeotropic orientation of LC suppressed the flow induced instabilities and the slow motion of water droplets mentioned above. It also induced the aggregation of droplets in the vicinity of boundary between regions with strong field and free of field. So, combined action of shear flow and electric field can be effectively used for manipulation of the motion and interaction of water droplets. The obtained results are discussed within the existing theory of liquid crystals.