Study on orientation of nematic liquid crystal at PI surface by molecular dynamic simulation

• Main Authors: Po-Wen Yu, 游博文
• Other Authors: 陳鐵城
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/96563396527706504431

碩士 === 國立成功大學 === 機械工程學系碩博士班 === 97 === In this study, we study on orientation of nematic liquid crystal at polyimide substrate by molecular dynamics simulation and use united atom model to simplify all hydrogen atoms of liquid crystal and polyimide. The advantage of united atom model greatly reduces computation times and increases computational efficiency which is in agreement with experiment. The liquid crystal display contains glass substrate, color filter, polarizer, and alignment layer. The anchoring strength between the molecular structure of alignment layer and liquid crystal affects alignment of the liquid crystal on alignment layer when the electric field does not apply. This article discusses the effect of alignment layer composed of polyimide and the different shape of microgroove ( V- and square-shaped ) which influences the alignment of liquid crystal. The alignment of liquid crystal is represented by order parameter. The result of this study shows that liquid crystal orients in a direction perpendicular to the polyimide main chain direction and the molecular orientation of liquid crystal is influenced by the shape of microgroove. For the V-shaped polyimide liquid crystal alignment layers, the order parameter of liquid crystal is higher compared with that from the square-shaped polyimide liquid crystal alignment layers.