Liquid crystal alignment surface with two easy axes induced by unidirectional rubbing

We report the liquid crystal (LC) alignment surface which has two orthogonal easy axes induced by a unidirectional rubbing treatment. When the photoreactive polymer with chalconyl sidechains is irradiated with nonpolarized UV light and subsequently rubbed with a cloth, LCs align parallel and perpendicular to the rubbing direction on the UV irradiated and nonirradiated surfaces, respectively. The polarized UV absorption of the polymer and the sign of the dichroism are measured to explain the alignment mechanism. The micropatterning of the LC alignment is successfully demonstrated through the simple process using a photomask and nonpolarized UV irradiation technique. (C) 2003 American Institute of Physics.