經由紫外光配向程序之液晶混合系統（垂直配向模式）的相轉移行為與灰階特性探討

Phase-Transition Behaviors and Gray-Scale Characteristics of the Liquid Crystal Mixtures System (Vertical Alignment Mode) with Ultra-Violet Photo-Alignment Process

本研究為利用具有乳酸結構的雙旋光中心液晶 （two chiral centre liquidcrystals） 材料，於實驗中以偏光顯微鏡 （polarized optical microscopy, POM） 觀察此液晶材料從等向性溫度 （isotropic temperature） 降溫至出現雙旋光性層列型液晶 （SmA*） 相時，會產生垂直排列紋理 （homeotropic texture） 的現象。我們希望藉由將雙旋光結構SmA*液晶摻入光致垂直配向的負誘電異方性液晶（向列型液晶）／壓克力單體混合系統，以達到輔助液晶分子整體垂直排列效果。而在此液晶混合系統之垂直配向模式下，我們以POM 來觀察液晶分子排列的情況以及利用示差掃描熱分析儀 （differential scanning calorimeter, DSC）來探討其液晶相轉移行為。最後，也探討其液晶混合系統的灰階特性。

In this study, we observe the lactic acid structures (two chiral centreliquid crystals) of liquid crystal material, and the homeotropic texturephenomenon utilizing polarized optical microscopy (POM) from an isotropictemperature down to the temperature at which SmA* appears. Weexpect to obtain two chiral structure SmA* LC by mixing photo-inducedvertical alignment (VA) negative dielectric anisotropy LC (Nematic typeLC) and acrylic monomer mixture systems to achieve overall LC moleculesarranged in a vertical alignment. In addition, we have observed theLC molecules arrangement condition in the VA mode of the LC mixturesystems by POM and investigated LC phase-transition behaviors by differentialscanning calorimeter (DSC). Finally, the gray-scale characteristicsof the LC mixture systems have also been explored.