本論文將會對所合成寬廣溫度的藍相液晶化合物進行設計、合成與液晶性質探討。 藍相液晶應用於顯示器上會優於市面上的向列相液晶，其展現出短的應答時間、在顯示器暗態時為光學各相同性與不需要配相層等優勢。但已發表的藍相液晶之藍相只能維持在一個狹隘的溫度範圍 (約2 oC)，使得其難以使用在液晶顯示器上。 為了獲得寬廣溫度範圍的藍相液晶，穩定雙扭轉柱體分子排列結構是必須的；而文獻報導雙光軸液晶預期可促使藍相穩定生成。另透過不對稱分子設計及環狀官能基團改變，藍相液晶生成溫度有機會進入室溫範圍以利於實際應用。 因此將分子設計成不對稱交叉狀構形並引入掌性側鏈，成功誘導生成寬廣溫度藍相，利用偏光顯微鏡與粉末X光繞射證實其雙光軸性質。接著對側臂官能基團進行改變，使藍相液晶相溫度範圍趨近涵蓋室溫。 In this thesis, the design, synthesis and liquid crystal properties of those wide-temperature-range room-temperature blue phase (BP) liquid crystals (LCs) are reported. Blue phase liquid crystals exhibit short response time, optically isotropic dark state, and no need for molecular alignment layers to outperform nematic LCs currently used in displays. However, reported BPLCs are usually formed within a narrow temperature range (about 2 oC), which is disadvantageous for practical display applications. For obtaining wide-temperature-range room-temperature blue phases, it is necessary to stabilized the double twisted cylinder molecular packing structures. Molecules showing biaxial liquid crystalline phases were known to be able to stabilize molecular packing suprastructures of blue phases. Herein, molecular design of the unsymmetrical cross-like geometry with chiral side-chains are practiced and blue phases of wide-temperature-ranges are achieved. By using POM and PXRD, biaxial properties of the nematic phase is confirmed. Further structural modification on the peripheral rings of the cross-like mesogens makes the temperature range of blue phases to nearly include room-temperature.
