多面體矽氧烷奈米粒子於液晶盒內配向特性探討

Abstract

近年來，多面體矽氧烷奈米粒子(Polyhedral Oligomeric Silsesquioxanes，POSS )參雜於液晶盒內形成垂直配向的液晶元件已有許多方面的應用。在本研究中，我們利用正丁醇溶液與多面體矽氧烷奈米粒子混合當作配向膜使用，希望藉由改變不同POSS極性官能基以及不同的液晶盒製作步驟來探討POSS在ITO玻璃上的成膜特性及其所引發之垂直配向機制和光電特性。 實驗結果發現POSS配向膜經過旋轉塗佈在ITO玻璃上後能使液晶產生垂直配向，但是薄膜表面會隨著極性官能基的不同形成不同大小及形狀的POSS團聚且會造成暗態漏光現象，然而經過加溫再成膜步驟後可以改善團聚的現象，最後藉由摩擦配向步驟可以提升POSS液晶盒的穿透率。利用外加高電場的方式可以得到POSS液晶盒的錨定能約為1.3x10^-4(J/m^2) ，且當受到熱擾動時，會造成POSS液晶盒垂直配向能力的下降。

In recent years, vertically-aligned liquid crystal devices doped with polyhedral oligomeric silsesquioxanes (POSS) nanoparticle have shown many applications. Different kinds of POSS polar function group and manufacture processes were used to investigate the vertical alignment mechanism and the electro-optical properties of POSS alignment layer. According to the experimental results, three kinds of POSS could induce vertically-aligned in LC cells, however, light leakage in the dark state was observed due to POSS aggregation. After baking POSS alignment layers above POSS melting point, POSS aggregation disappeared and produced a surface with less roughness. The transmittance of LC cells could be improved by the rubbing treatment. Based on the high electric field method, the anchoring energy of POSS alignment layer was determined as1.3x10^-4(J/m^2).