臺灣博碩士論文加值系統

本論文利用螺旋扭轉力(helical twisting power)及擴展Jones 4X4矩陣(extended Jones 4x4 matrix method)之理論來模擬擴展膽固醇液晶的反射頻帶。
研究中使用向列型液晶5CB/JC-1041XX(1：1 w/w)，手性摻雜劑由軸手性聯萘與偶氮苯單體組成，發現經過溫度的增加，或是手性摻雜劑濃度的減少，所模擬之膽固醇液晶螺距會有變長的現象，依此現象模擬不同溫度及手性摻雜劑之摻雜濃度，造成膽固醇液晶螺距的梯度變化。室溫下，固定摻雜濃度5wt%，反射光譜之頻帶寬度大約為36nm，溫度從室溫上升至55℃，反射光譜之頻帶寬度會增加至160.5nm；室溫下，摻雜濃度從5wt%減少至3.5wt%，反射光譜之頻帶寬度會增加至197nm。另外使用cholesteryl oleyl carbonate/cholesteryl chloride 80.1/19.9 (mole %)進行壓力梯度的模擬，在壓力梯度下，頻帶寬度會有明顯的增加。藉由溫度、摻雜濃度與壓力的變化，探討對螺距與反射頻帶的影響。

In this thesis, the broadening of the reflection band of cholesteric liquid crystals is simulated by considering the helical twisting power and extended Jones 4x4 matrix method.
In the research, the nematic liquid crystals 5CB/JC-1041XX (1：1 w/w) were used. The chiral dopant is comprised of axially chiral binaphthyl with azobenzene units. It was found that the increasing temperature or decreasing concentration of chiral dopant result in the increasing pitch of cholesteric liquid crystals. According to these phenomena, different concentrations of chiral dopant and different temperature gradients were simulated, which induced a gradient variation of pitches in the cholesteric liquid crystals. At room temperature, at the fixed 5wt% concentration of chiral dopant, the bandwidths of the reflection spectra were approximately 36nm.When the temperature increased from the room temperature to 55°C, the bandwidth of the reflection spectrum increased to 160.5nm. At the fixed room temperature, the concentration of chiral dopant decreased from 5wt% to 3.5wt%, the bandwidth of the reflection spectrum increased to 197nm.
In addition, cholesteryl oleyl carbonate/cholesteryl chloride 80.1/19.9 (mole %) were used to simulate pressure gradient. Under the pressure gradient, the bandwidth of the reflection spectrum increased obviously.
The influences of the changes in the temperatures, the concentrations of chiral dopant and pressure on the pitches of cholesteric liquid crystals and the bandwidth of the reflection spectra were discussed.

摘要......................................................i
Abstract.................................................ii
誌謝......................................................iii
目錄......................................................iv
表目錄....................................................vi
圖目錄....................................................vii
第一章 緒論...............................................1
1.1 研究動機..............................................1
1.2 研究目的..............................................1
第二章 文獻探討............................................2
2.1 液晶的歷史.............................................2
2.2 何謂液晶...............................................2
2.3 液晶分類...............................................3
2.3.1 長條狀(Rod-like)液晶分子..............................4
2.3.2 向列相液晶(Nematic Liquid Crystal)....................4
2.3.3 近晶相液晶(Smectic Liquid Crystal)....................5
2.3.4 膽固醇相液晶(Cholesteric Liquid Crystal)..............6
2.4 膽固醇液晶的排列結構.....................................7
2.5 液晶分子的秩序參數(order parameter)......................8
2.6 液晶的介電異向性(Dielectric Anisotropy)..................9
2.7 液晶的光學異向性(Optical Anisotropy).....................9
2.8 液晶的彈性常數(Elastic Constant)........................10
2.9 波板(Wave Plate).......................................10
第三章 研究內容與方法......................................13
3.1 理論介紹...............................................13
3.1.1 膽固醇液晶光學特性....................................13
3.1.2 Extended Jones Matrix Method........................14
3.1.3 熱傳導定律...........................................23
3.1.4 菲克定律.............................................23
3.1.5 應力分布.............................................23
3.1.6 溫度下螺旋扭轉力(HTP)和濃度對膽固醇液晶螺距的影響.......24
3.1.7 壓力對膽固醇液晶螺距的影響.............................24
3.2 模擬參數...............................................25
3.2.1 溫度與chiral dopant濃度相關之模擬參數..................25
3.2.1 壓力相關之模擬參數....................................26
第四章 結果與討論.........................................28
4.1 固定溫度，固定chiral濃度................................28
4.2 固定chiral濃度，溫度做梯度變化...........................30
4.3 固定溫度，chiral濃度做梯度變化...........................36
4.4 固定壓力................................................43
4.5 壓力做梯度變化..........................................46
第五章 結論...............................................50
參考文獻....................................................51
附錄一：溫度分布............................................53
附錄二：濃度分布............................................55
附錄三：應力函數推導.........................................56
Extended Abstract..........................................58

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