Use of Catastrophe Theory to the Study of Large-Scale Fluctuations in Nematic Droplets Prepared Under Magnetic Field

Abstract
In the framework of catastrophe theory the large-scale fluctuations in droplets of nematic 5CB prepared by solution technology under magnetic field have been studied. From the analysis of the potential curves it was found that the fluctuations caused by the variation of the nematic director between potential minima connected with the anchoring energy of a liquid crystal-polymer and magnetic field. A relation between the control parameters of cusp catastrophe with the anchoring parameters has been determined. The influence of magnetic field on the control parameters leading to a structural transition in the droplet of the liquid crystal that corresponds to the director transformation of the bipolar structure with extended pole to a radial configuration has been analyzed. On the basis of the performed analysis the values of the anchoring energies of the liquid crystal with the polymer surface were estimated.

Keywords: nematic, polymer, anchoring energy, cups catastrophe, control parameters, structural transition