臺灣博碩士論文加值系統

本論文主要是研究向列型液晶(E7)在變溫過程中黏滯係數的變化量測，實驗上主要是藉由偏光顯微鏡與示差熱掃描分析儀測定液晶相變點溫度，並使用圓錐-平板式黏度計量測溫變時液晶黏滯係數，同時藉由偏光顯微鏡觀察液晶(E7)隨溫度變化時相變的行為、發現相變狀態是一連續非均勻的混合態變化，並探討其黏滯係數與溫度之關係，經由本實驗結果發現，液晶(E7)的相變是經過一個與溫度有關的範圍，而不是一般物質的單一相變點，此種現象從未被證實過。

In this thesis, we investigated the viscosity coefficient of liquid crystal (LC) - E7, with its temperature dependence. In the experiment, we used the polarizing optical microscopy (POM) and Differential Scanning Calorimeter (DSC) to monitor the transition process of liquid crystal. To study the transient behavior of E7, we used the Cone and Plate Viscosmeter to measure the temperature-dependent viscosity coefficient. The POM experimental results show that the phase transition of E7 is a continuous and nonhomogeneous phenomenon depending on the temperature. According to the result, we could analyze the relationship of viscosity coefficient and temperature by calculating the volume ratio in the different states.
We found the there is a window for phase transition process of E7, but not a critical temperature point. This result is a new finding and different from any previous investigations. This research will give important information to the fundamental understanding of the phase transition of LC.

書名頁 i
授權書 ii
論文口試委員審定書 iii
中文摘要 iv
英文摘要 v
致 謝 vi
目 錄 vii
圖 錄 x
表 錄 xiii
第一章 緒論 1
1.1 前言 1
1.2 向列型液晶黏滯係數 4
1.3 文獻回顧 5
1.4 向列型液晶(Nematic Liquid Crystal) 7
1.5 實驗用液晶材料 13
第二章 實驗操作 14
2.1 實驗方法 14
2.2 黏度計量測原理 15
2.3 實驗儀器 16
2.4 黏滯係數的量測 16
2.5 相變點溫度測定 20
　　2.5.1 偏光顯微鏡(POM) 20
　　2.5.2 示差掃描熱分析儀(DSC) 20
2.6 POM樣品的製備 22
第三章 實驗結果分析與討論 24
3.1 液晶相變點溫度確認 24
　　3.1.1 使用偏光顯微鏡 24
　　3.1.2 使用示差熱掃描分析儀 27
3.2 使用圓錐平板式黏度計量測向列型液晶的黏滯係數 29
3.3 偏光顯微鏡觀測液晶相變過程 38
3.4 公式擬合混合態時的液晶相黏滯係數與液相黏滯係數 40
3.5 公式擬合分析液晶相與液相體積比 41
第四章 結論 52
參考文獻 53

本論文中的實驗結果已在中國液態晶體學會與積體光機電科技應用與發展學術研討會發表。
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