近年來藍相液晶的光電特性受到國際間相當的重視，如藍相液晶的存在溫度範圍、藍相液晶對電壓的穩定性等，而大部分藍相液晶的存在溫寬都非常狹窄，尋求拓寬藍相液晶存在溫寬的方法因而顯得非常重要，目前最主要被應用於拓寬藍相液晶溫寬的方式為高分子聚合穩定藍相液晶，有別於利用高分子聚合物，本論文探討旋性聚合物在藍相液晶中的光電特性，並與一般高分子聚合物的效應做比較。 實驗結果顯示，旋性聚合物摻雜藍相液晶進行光聚合後可拓寬藍相液晶存在溫寬，為探討旋性聚合物拓寬藍相液晶存在溫寬的機制，本論文討論以下幾種不同變數的效應：(1)手性分子與手性聚合物摻雜濃度、(2)聚合物受光聚合時的相態、(3)聚合物受光聚合時間、(4)樣品厚度等。經由不同參數的改變，發現摻雜高濃度手性聚合物的樣品在均向態經紫外光照射進行聚合反應，可將藍相溫寬拓寬至30oC以上，根據文獻指出一般聚合物在均向態下進行光聚合反應以拓寬藍相溫寬的效果較差，因此摻雜旋性聚合物較一般聚合物可更有效且簡單地拓寬藍相溫寬。另外，此方式所得到藍相液晶的光電特性亦不亞於一般聚合物所拓寬的藍相液晶，也因少了聚合物在液晶盒內部之網絡結構的影響，故可提供更快速的反應速度。最後，我們提出其機制模型以說明本論文所發現的現象，相信此成果將對藍相液晶未來之技術發展有相當之助益。 ;Recently, the electro-optical characteristics of blue phase liquid crystals (BP-LCs), such as the temperature range, stabilization as applying voltages, etc, have been paid much attention significantly. Moreover, the temperature range of BP-LCs is definitely narrow. It is clear that the extension of temperature range is one of the key points in BP-LCs field. Polymer-stabilized blue phase is the most commonly used method to extend the temperature range of BP-LCs. In this thesis, the electro-optical properties of chiral polymer-doped BP-LCs, as well as the comparisons between achiral and chiral polymers, are reported. According to the experimental results, the polymerized chiral polymer onto the substrates can be used to extend the temperature range of BP-LCs significantly. To elucidate the mechanism for extending the temperature range of BP-LCs, several factors for the processes of photo-polymerization are considered. They includes (1) concentration of chiral dopant and chiral polymer; (2) LC phase (cholesteric, blue, and isotropic phases) during photo-polymerization; (3) curing duration; (4) cell gap, and others. It is demonstrated that the temperature range of BP-LCs can be extended to 30oC by polymerizing chiral polymer (6 wt%) polymerization in isotropic phase. Refer to some references; the extension of temperature range of BP-LCs via polymer stabilization can only be achieved by polymerizing achiral polymer in LC blue phase. Thus the proposed method (chiral polymer) is much easier than the conventional one (achiral polymer) to extend the temperature range of BP-LCs. Additionally, the electro-optical properties of chiral polymer-stabilized BP-LCs are as good as those of polymer-stabilized BP-LCs.
