臺灣博碩士論文加值系統

本實驗利用手性分子及二氧化矽奈米粒子摻雜進正型液晶中將其製作成具有雙穩態及動態操作模式的散射樣本。根據一些佐證文獻可以知道矽奈米粒子有帶負電，具有可電泳的特性，能使用脈衝電壓使其發生電泳效應(electrophoresis)控制矽奈米粒子往正脈衝直流電壓側的玻璃基板移動，當放掉電壓後矽奈米粒子仍然會保持在同一側，除非加入新的脈衝直流電壓。利用以上矽奈米粒子特性並結合手性分子(chiral)使液晶分子扭轉的特性，搭配單面垂直配向基板(另一側為無配向基板)製成normal mode的散射樣本，此樣本具有雙操作模式，雙穩態時在無配向側加入正脈衝電壓使矽奈米粒子電泳至該側基板並穩固液晶分子使其垂直排列，這時樣本呈穿透態；當正脈衝電壓加入垂直配向側時，矽奈米粒子離開無配向側基板，這時液晶分子的排列是雜亂的，此時呈現散射態。動態模式時，樣本的散射態會依外加電壓大小而改變，電壓越大樣本的散射情況就越弱，樣本此時就越穿透。

In this experiment, chiral molecules and silica nanoparticles were doped into liquid crystals (LCs) with positive dielectric anisotropy to create a scattering sample with bistable and dynamic operating modes. According to supporting references, silica nanoparticles are negatively charged and exhibit electrophoretic behavior, allowing them to be controlled by applying pulsed voltages. By applying a pulsed direct current (DC) voltage, the silica nanoparticles can be moved towards the glass substrate on the positive pulsed side. Once the voltage is released, the nanoparticles remain on that side until a new pulsed DC voltage is applied. By utilizing the characteristic of silica nanoparticles and combining them with the chiral molecules, a normal mode scattering LC sample was fabricated, utilizing one vertical alignment substrate and the other substrate with no treatment. This LC sample exhibits two operating modes. In the bistable mode, by applying a positive pulsed voltage on the substrate without alignment, the silica nanoparticles move toward that side's substrate, stabilizing the LC molecules into a vertical orientation, resulting in a transparent state. When the positive pulsed voltage is applied on the vertically aligned side substrate, the silica nanoparticles detach from the side without alignment, causing the liquid crystal molecules to be disordered in the bulk, resulting in a scattering state. In the dynamic mode, the scattering state of the sample varies with the magnitude of the applied voltage. Applying higher voltage cause the scattering weaker and then the sample becomes more transparent.

摘要......i
Abstract......ii
誌謝......iii
目錄......iv
表目錄......vii
圖目錄......viii
符號說明......x
第一章 緒論......1
1.1 前言......1
第二章 相關理論......2
2.1 液晶的起源......2
2.2 液晶的定義......2
2.3 液晶的分類......3
2.3.1 盤狀分子......3
2.3.2 棒狀分子......4
2.4 液晶物理......9
2.4.1 液晶的光學異向性(optical anisotropic)......9
2.4.2 介電異向性......11
2.4.3 Freedericksz Transition......13
2.4.4 溫度的影響......13
2.4.5 連續彈性體理論......14
2.5 DMOAP垂直配向......15
2.6 液晶的相位延遲(Phase Retardation)......17
2.7 膽固醇液晶簡介......19
2.8 電泳動原理......21
2.8.1 Helmholtz Electric Double Layer......22
3.1 材料介紹......23
3.1.1 向列型液晶: E7......23
3.1.2 二氧化矽奈米粒子：Aerosil®R812......24
3.2 樣本製作......24
3.2.1 調配材料......24
3.2.2 清洗玻璃......24
3.2.3 玻璃基板垂直配向鍍膜......25
3.2.4 樣本製作......25
3.3 實驗架設及量測......27
3.3.1 穿透度-電壓曲線......27
3.3.2 樣本光譜圖......28
3.3.3 轉偏振量測......29
3.3.4 反應時間量測......30
第四章 結果與討論......31
4.1 手性分子濃度對樣本光電特性影響......31
4.1.1 偏光顯微鏡圖下對於樣本有無手性分子的探討......31
4.1.2有無摻雜Chiral樣本的穿透率-電壓曲線......32
4.1.3 不同手性分子對散射樣本的影響......33
4.1.4 摻雜Chiral樣本POM及T-V curve探討......34
4.2不同厚度之摻雜Chiral樣本的光電特性......35
4.2.1 樣本光譜圖及T-V Curve ......35
4.2.3 樣本厚度過高對於穿透穩態的影響......37
4.2.3 樣本反應時間......38
4.3 不同Chiral濃度測試......39
4.3.1不同Chiral濃度之電壓對穿透率曲線......39
4.3.2不同Chiral濃度樣本之偏光顯微鏡圖......40
4.4 雙穩態操作模式......41
第五章 結論...43
參考文獻......44
Extended Abstract......46

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