Mechanism in determining pretilt angle of liquid crystals aligned on fluorinated copolymer films

作者:Wu Hsin Ying*; Wang Chih Yu; Lin Chia Jen; Pan Ru Pin; Lin Song Shiang; Lee Chein Dhau; Kou Chwung Shan
来源:Journal of Physics D: Applied Physics , 2009, 42(15): 155303.
DOI:10.1088/0022-3727/42/15/155303

摘要

This work explores the surface treatment of copolymer materials with fluorinated carbonyl groups in various mole fractions by ultraviolet irradiation and ion-beam (IB) bombardment and its effect on liquid crystal (LC) surface alignments. X-ray photoemission spectroscopic analysis confirms that the content of the grafted CF(2) side chains dominates the pretilt angle. A significant increase in oxygen content is responsible for the increase in the polar surface energy during IB treatment. Finally, the polar component of the surface energy dominates the pretilt angle of the LCs.