Kurioz Y. Nematic liquid crystals reorientation in the cells with photosensitive aligning layers

Optical-, magnetic- and electric-driving director reorientation of nematic liquid crystal (LC) in the cells with photosensitive aligning layers were investigated. LC cells have planar, homeotropic and oblique orientation. We investigated effect of director reorientation in a polar plane of a LC cell due to smooth change of anchoring parameter of liquid crystal by the aligning surface. It was determined that the reorientation of the director under influence of light was threshold in the cells with homeotropic orientation of LC and not threshold in the cells with hybrid orientation. We founded the effect of director reorientation in azimutal plane of LC cell because of light-induced change of liquid crystal anchoring parameter on an aligning surface at irradiation with fixed polarization state. The reorientation of LC is appeared in a change of an easy orientation axis from parallel to perpendicular in relation to the initial one at time exposure increasing. The effect of magnetic-controlled photoorientation of liquid crystals was investigated. The irradiation of a surface with photosensitive polymer PVCN-F at simultaneous magnetic field action results in bistable oblique orientation of nematic LC 5CB. The electrically-controlled director reorientation in a plane of photoorientant with controlled anchoring energy was investigated and the new mode of reorientation of the director - mode of director sliding was developed. It enables to realize a new mode of director reorientation, which work is based on effect of LC director sliding on a photoaligning surface with weak anchoring energy.