Multidirectional alignment of liquid crystals on polystyrene surface

The dipole-dipole interaction between liquid crystals (LCs) and a polystyrene (PS) surface induced by ion beam (IB) irradiation was successfully studied. The LC molecular orientation follows the IB alignment direction on the PS surface, upon IB irradiation or rubbing. The LC orientation on the PS surface is fixed by IB irradiation and is not affected by rubbing. Also, the LC alignment direction depends strongly on the C=O bonds formed from the C=C and C-C bonds on the PS surface that are broken by the IB irradiation. The LC alignment induced by IB irradiation on the PS surface using dipole-dipole interaction between the LCs and the PS surface is more strongly affected by the chemical bonding of broken chains than by physical processes such as the microgroove effect and π-π interaction. Furthermore, the anchoring strength of LCs on the PS surface upon IB irradiation is stronger than that of the PS surface upon rubbing as indicated by the LC orientation direction.