Topological defects arrays and control of electro-convections in periodically photo-aligned bent-core nematics

The applicability of photo-alignment technique to bent-core nematics (BCN) is demonstrated in this paper. In order to cope with the inherent problems of BCN such as high working temperature and large working current, a photo-alignment technique, based on two superimposed photosensitive layers of azo and reactive mesogen, is used to produce symmetric and asymmetric planar alignments. With various surface conditions, defect lines arrays are self-assembled and ac-driven electro-convection (EC) rolls are modulated. Further inspections indicate that the defect lines arrays and EC rolls are in a competitive state, which reveal that the EC rolls in BCN belong to nonstandard EC scenarios. By producing defect lines and modulating EC rolls via photo-alignment technique, we could customize patterns in liquid crystals towards new photonic devices.