Molecular Crystals and Liquid Crystals, Vol.512, 1998-2003, 2009
Inverse Mode of Ion-Surfactant Method of Director Reorientation Inside Nematic Droplets
Inverse mode of a novel electrooptical effect caused by the ionic modification of boundary conditions has been studied for liquid crystal droplets. We have considered the droplets of nematic 5CB doped with cationic surfactant cetyl-trimethyl-ammonium-bromide and dispersed in polyvinyl alcohol. In the initial state the surface anchoring was normal on the whole interface due to the high concentration of homeotropic surfactant. Applied voltage results in the purification of a section of the interface from the surface-active cations thereby restoring here a tangential anchoring and stimulating the significant transformation of droplet structure. At that three different types of director field distribution can be realized within the same droplet. The proper textures of the droplet both in the crossed polarizers and without analyzer are considered.
Keywords:electrically commanded surfaces;ion surfactant;nematic;polymer dispersed liquid crystals;surface anchoring