Self-shaping of liquid crystals into superstructures for photonic applications

We discuss the growth and shape stabilization of small objects made of smectic and nematic liquid crystals (NLCs) in aqueous surfactant solutions. When dispersed or put in contact with an aqueous solution of CTAB, smectic A liquid crystals spontaneously grow into fibers of very uniform diameter and good optical quality, which makes them appropriate for light guiding applications. However, it is difficult to control the growth of smectic A fibers and attempts to stabilize them by photo polymerization fail to produce good quality structures for optical application. We discuss a novel method for self-shaping of nematic liquid crystal droplets into various LC fibers. The method is based on the use of two surfactants: one is dissolved in the LC and the other in the aqueous phase. By changing the temperature, the surface of the droplet increases at a fixed volume of the LC, which triggers the transformation of a droplet into fibers. This is a novel mechanism of LC droplet shape transformation, where the surface of the LC interface is controlled by the temperature and concentration of two surfactants.