Control of Liquid Crystal Pretilt Angle Induced by Dipole-dipole Interactions on Inorganic Thin Film Surfaces
In this work a-SiOx film surfaces irradiated by the low-energy Ar ion beam for the liquid crystal alignment are investigated by using AFM( atomic force microscopy), KFM( Kelvin probe force microscopy), and the contact angle method. We found that whether liquid crystal can be aligned vertically on a-SiOx film has nothing to do with the surface morphology observed by AFM measurement, but liquid crystals can be aligned vertically when high values of electric potential roughness are observed at the a-SiOx film surface. We also found that a-SiOx films for vertical alignment show high contact angles, while those for homogeneous alignment show small contact angles. All experimental results show us consistently that Coulomb interaction between liquid crystal molecules and the ionized film surface has a dominant effect upon liquid crystal alignment on inorganic film surfaces by the low-energy ion beam exposure. We also propose a method to fabricate a multidomain liquid crystal cell on a-SiOx by controlling the direction of the ion beam exposure.
Nematic Liquid Crystal Amorphous SiOx Vertical Alignment KFM Contact Angle Coulomb Interaction
Phil Kook Son Jeung Hun Park Sung Su Cha Joung Ha Lee Jae Chang Kim Tae-Hoon Yoon
Department of Electronics Engineering, Pusan National University, Busan 609-735, Korea
国际会议
上海
英文
1148-1153
2007-03-12（万方平台首次上网日期，不代表论文的发表时间）