Liquid Crystal Alignment Behaviors on Comb-Like Fluorinated Polystyrene Films

ABSTRACTWe synthesized a series of fluorinated polystyrene (PCMSF#, # = 50, 80, and 100), where # is the molar content of 1H,1H,2H,2H-perfluorodecanethiolate moiety, using polymer analogous reactions to investigate their liquid crystal (LC) alignment properties. In general, the LC cell fabricated using the polymer film having a higher molar content of fluorinated side group showed vertical LC alignment behavior with a pretilt angle of about 90°. The vertical alignment behavior was well correlated with the surface energy value and fluorine atomic percent of these polymer films. For example, vertical alignment was observed when the surface energy values of the polymer were smaller than about 8.77 mJ/m2 generated by the nonpolar and long fluorocarbon groups. Good electro-optical characteristics, such as voltage holding ratio (VHR) and residual DC voltage (R-DC), and aligning stabilities at 250°C were observed for the LC cells fabricated using PCMSF100 as a LC alignment layer.