Melting of Nematic Liquid Crystals with Predesigned Topological Defect Arrays*

Dynamics of transitions between phases of different translational and/or orientational ordering is a fascinating area of intense studies. Topological defects are well known to play an important role in the phase transitions as an essential means of symmetry breaking. In this talk, we will present experimental studies on the melting transition of thin nematic liquid crystals with predesigned molecular orientation patterns of topological defect arrays. We found that the heating rates and topological charges have critical impacts on whether defect-mediated heterogeneous or homogeneous nucleation and growth dominate the process. We also found that in all situations, the growth of isotropic domain sizes follows a simple power law of the temperature and that the exponent can be either 0.5 or 1, depending on the heating rate and topological charges.