Liquid crystal photoalignment properties of polymethylphenylsilane

Polymethylphenylsilane PMPS., prototype of polysilanes, is considered as photoaligning material for liquid crystals LC.. The LC photoalignment on PMPS is characterized by the singular low exposure energy EF50 mJ.necessary to produce LC alignment. Dependence of the azimuthal anchoring energy Wa on the exposure time texp is non-monotonous; curve W texp.sharply increases, goes through a maximum and decreases to the values close to zero. The easy axis of LC alignment is induced in the direction of light polarization. Possible microscopic mechanisms of LC photoalignment on PMPS layers are discussed. q2000 Elsevier Science B.V. All rights reserved.