Director structures in achiral smectic C liquid crystal cells: field‐induced twist domain nucleation

Abstract

The electro‐optic response of two achiral smectic C liquid crystals, W479 and 8¯S5, in thin surface stabilized cells has been studied using polarizing optical microscopy. In their virgin (field‐free) state, W479 cells have ‘bookshelf’ structure, with the smectic layers uniformly tilted with respect to the bounding glass plates, while 8¯S5 cells have bent or ‘chevron’ layering. Upon first cooling into the smectic C phase, both materials exhibit domains of uniform optic axis orientation. Subsequent application of an electric field leads to a Fréedericksz transition and to the nucleation and growth of non‐uniform domains in which the optic axis is twisted. Models for the virgin and field‐induced director structures are proposed.

Acknowledgements

The authors wish to acknowledge Z. Zhuang for assistance with the initial optical studies of 8¯S5, and N. Chattham for confirming the anticlinic phase structure of W479 in freely suspended films. This work was supported by ED GAANN Fellowship P200A030179, NSF MRSEC Grants DMR‐9809555 and DMR‐0213918, ARO Grant DAAG55‐98‐1‐0446, and NSF Grant DMR‐0072989.