United Atom是分子動力學中模擬高分子的一種方式，其主要是由於龐大計算量因應而生，United Atom也可看成CGMD (Coarse-Grained Molecular Dynamics)的其中一種，其優點即減少不必要的龐大計算量，又能兼顧模擬結果跟實際的吻合度。液晶顯示器的最佳化設計一直是近年來研究的主要議題，其中面板結構中配向膜上的溝槽結構，其產生的錨定力對未加電場前的液晶有重要的配向影響，故未加電場前配向膜上的液晶配向，是影響其顯示效能的其中一個重要因素。本文主要運用分子動力學模擬小尺度下，在PI分子組成的配向膜上，製作不同溝槽深寬比對液晶配向的影響，而配向的優劣主要是依據有序參數的大小。模擬結果顯示，基板上製作奈米尺度的溝槽確實有助於提高液晶分子的有序參數；但是，單純改變溝槽深度、寬度、或其比值，對有序參數的影響則並無顯著的規則性。

United atom is a method to simplify a large molecule, that is generally composed of several kinds of atoms, to a few particles. Consequently, the time of calculation can be significantly reduced. In other words, the method of united atom can be also considered as a special kind of Coarse-Grained Molecular Dynamics. The optimum design of liquid crystal display has attracted great attention in recent decade. The microgroove on the substrate may improve the alignment of liquid crystals on the layer. The anchoring strength due to the microgroove structure on the alignment layer can also be effectively enhanced. It means the alignment of liquid crystal is the point for the performance of liquid crystal display. The main objective of this study is to investigate the influence of microgroove on the alignment of the liquid crystals by molecular dynamics analysis. The effects of the depth and the width of microgroove on the alignment of liquid crystals are also estimated by using the order parameter. It is found that the adoption of microgroove in nanometer scale does improve the order parameter of liquid crystals by approximately 10%. However, the tendency of influence is not clear by only changing the width, the depth, or the ratio of microgroove.

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