Cyanobiphenyls surface alignment

Static force [45,50,51,57] and friction properties [45,46,51,57-59] have been extensively studied in thermotropic nematics. The surface anchoring conditions were symmetric, with both mica sheets inducing either planar or homeotropic alignment. Bare mica naturally induces planar anchoring on cyanobiphenyls such as 5CB the liquid crystal optical axis orients at abont 7t/6 with respect to the slow optical direction of a (birefringent) freshly cleaved mica sheet [60]. A homeotropic ahgnment can be obtained by adsorbing a mono-layer of surfactant [45,50] on mica. 

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