Topological Defect Structure and Annihilation in High-Polarization Freely Suspended Films

The texture of freely suspended liquid crystal SmC* films of a high polarization material C7 [4-(3-methyl-2-chloropentanoyloxy)-4'-heptyloxybiphenyl] is studied using polarized light microscopy. In particular, we focus on c-director defects with topological strength --1 found in the chessboard texture. Due to the competition between the elastic energy and the electrostatic energy of polarization splay, the c-director field near the defect core consists of four domains with homogenous orientation of the c-director inside each domain. The boundaries between domains are sharp and the c-director orientation jumps by 90 degrees at each boundary. We will present experimental and theoretical studies of the structure of these polarization-stabilized discontinuities. We will also present studies of the annihilation dynamics of +1 and --1 pairs of defects on this high-P material film and compare them to those on low-P material films. [1] E. Demikhov, Europhys. Lett. \textbf{25} (4), 259 (1994). [2] E. Demikhov and H. Stegemeyer, Liq. Cry. \textbf{18}, 37 (1995). [3] Ch. Bahr and G. Heppke, Phys. Chem. \textbf{91}, 925 (1987). [4] D. R. Link, N. Chattham, J.E. Maclennan, and N.A. Clark, Phys. Rev. E \textbf{71}, 021704 (2005). This work is supported by NSF MRSEC Grant DMR0213918.