盤狀及T字型分子之合成與性質探討以及反射式液晶顯示元件之組裝

Synthesis and Properties of Disk-Shaped and T-Shaped Molecules, and Study on Characteristics of Reflective Liquid Crystal Display

葉睿祐(Jui-Yu Yeh)

指導教授 ： 黃俊誠

大同大學/工程學院/化學工程學系所/碩士(2011年)

摘要

本研究分為三部分，分別探討盤狀咪唑衍生物及T字形結構生成液晶相的可能性以及反射式液晶顯示元件之液晶材料測試
盤狀咪唑衍生物的部分，分別合成出氮原子上有無碳鏈之鍵結，以及不同的離子之相關衍生物。在化合物I5的NMR鑑定中有發現氫鍵之產生，但是因容易熱裂解所以不具有液晶相性質，而其他化合物可能受到碳鏈彎折影響，導致排列不佳，也沒有液晶相的生成。
T字形分子結構部分，參考Yoshizawa教授所發表之T字形結構，將雙苯環改成萘環，並將軟鏈拉長，期待能拓寬藍相液晶相溫度範圍，但測量結果發現，化合物T1熔點太低，經DSC測定無液晶相生成，可能與碳鏈太長有關。
反射式液晶顯示元件部分，分別以化合物N2*、化合物N3*及S811與向列型液晶N4摻混得到膽固醇液晶相，經注入液晶盒後，前兩者之膽固醇液晶相為指紋狀條紋，無反射性質出現，而20%至30%的S811與向列型液晶N4摻混後可得到具有反射性質之平板狀條紋，其雙穩態驅動電壓分別為8V以及32V。

關鍵字

盤狀分子 ； T字形分子 ； 膽固醇液晶

並列摘要

This research is composed of three parts, disc-like imidazolium derivatives, T-shape molecules and reflective liquid crystal displays.
In the first part, we synthesized a series of imidazolium derivatives with alkyl different groups on one nitrogen atom and various anions. In the 1H NMR spectrum of compound I5, the broad pattern of C-2 hydrogen is observed at δ 7-8 ppm possibly due to intermolecular hydrogen bonding. Unfortunately, it is thermally unstable and not liquid crystalline. Imidazolium derivatives with alkyl groups on two nitrogen atoms also do not show mesophases possibly due to the effect of curved alkyl chain on lattice arrangement.
In the second part, two different T shape molecules by replacing Prof. Yoshizawa’s core biphenyl group with naphthalene group are prepared with different alkyl chain length, to exhibit wider blue phase range than Prof. Yoshizawa’s compounds. However, compound T1’s melting point is below r.t., to possibly due to longer alkyl linkage.
In the study of reflective liquid crystal displays, cholesteric liquid crystal materials were obtained by doping compound N2*, N3* and S811 into nematic liquid crystal N4, respectively. The first two exhibit chiral nematic fingerprint texture and no Bragg reflection. S811 (20~30%) doped N4 shows Bragg reflection and chiral nematic planar texture. The driving voltages for bistable state are 8 V and 32 V respectively.

並列關鍵字

Cholesteric Liquid crystal ； T-Shaped Molecules ； Disk-Shaped Molecules

參考文獻

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