Electric field-induced nucleation and growth of focal-conic and stripe domains in a smectic A liquid crystal

Shila Garg, Kirstin Purdy, Erica Bramley, I. I. Smalyukh, O. D. Lavrentovich
2003 Liquid crystals (Print)  
We have studied the electric field-induced first order transition from a homeotropic smectic A structure to a polydomain texture that occurs through the nucleation of toric focal-conic domains (TFCDs). The process involves two steps: first, nucleation of TFCDs of a size larger than a critical radius a*, and then a steady growth of TFCDs to a secondary critical radius a**, when surface anchoring effects become dominant and cause a transition from a circular TFCD to an elongated stripe domain
more » ... . Studies were performed for pure smectic A materials and for smectic A doped with kunipia nanoparticles. Non-destructive 3D imaging with fluorescence confocal polarizing microscopy showed that field-induced TFCDs can nucleate in the smectic A bulk. Clay particles reduce the energy barrier for nucleation as they distort the smectic A layers and thus increase the ground state energy. Simple elastic models of the TFCD and SD allow us to describe the qualitative features of the observed phenomena.
doi:10.1080/02678290310001621886 fatcat:kcao5b3oxnevvezmiq4gpbvafa