臺灣博碩士論文加值系統

由於液晶彈性體具有液晶排列的次序性與聚合物網狀結構的彈性性質，因此具有獨特的性質。為了製備熱驅動性液晶彈性體，本研究使用偶氮苯單體(Azo Fulen)、合成的寡聚物和交聯劑(BAHB)來進行光聚合。並使用差示掃描量熱法(DSC)及偏光顯微鏡(POM)，找出液晶混合物的相轉移溫度。藉由紫外-可見分光光度法，測量材料的吸收光譜。在熱刺激下，液晶彈性體能多次的表現出可逆的驅動。這種現象歸因於熱酯交換和紫外光誘導的聚合，進而導致液晶彈性體有序參數S(order parameters)的記憶。研究結果顯示，合成的液晶彈性體膜能夠有效地將熱能轉換成機械動力。這個初步設計的熱敏性薄膜，期待在智能微型機器人系統中顯現出多樣實際應用的潛力。

The liquid crystal elastomers have unique properties because of combining liquid crystal orientational order with the elastic properties of a polymer network. To fabricate a thermal-responsive liquid crystal elastomer film, photo-polymerization of monomeric Azo Fulen, synthesized oligomer, and crosslinker BAHB was carried out. The transition temperatures of liquid crystal mixtures were confirmed using DSC and POM. The absorption spectra was measured using UV-Vis spectrometry. Under thermal stimulation, the polymerized liquid crystal elastomers show reversible actuation upon many cycles. This phenomenon is ascribed to thermal transesterification and UV induced polymerization lead to the memory of order parameters of LCEs. The results indicate that the synthesized liquid crystal elastomer film can effectively transfer thermal energy to mechanical power. The predesigned thermal-sensitive films are expected to show a number of potential for practical application in micro-robotic system with smart features.

Abstract I
中文摘要 II
Contents III
List of tables VI
List of figures VII
List of abbreviation XI
Chapter 1 General Introduction 1
1-1 Preface 1
1-2 Research Motivations 2
Chapter 2 Review and Theoretical Background 3
2-1 Introduction of Liquid Crystals 3
2-1-1 Historical Overview 3
2-1-2 Mesogenic molecules and orientational order 4
2-2 Classification of Liquid Crystal 9
2-2-1 Nematic Liquid Crystal Phase 11
2-2-2 Smectic Liquid Crystal Phase 11
2-2-3 Cholesteric Liquid Crystal Phase 14
2-2-4 Discotic Liquid Crystal Phase 15
2-2-5 Lyotropic Liquid Crystals 18
2-3 Introduction of Photo-polymerization Reaction 19
2-4 Introduction and Theory of Photochromic LC Polymers 21
2-5 Liquid Crystal Elastomers 22
2-5-1 Thermally induced actuation of LCEs 23
2-5-2 Photo-responsive actuation of LCEs 27
2-5-3 Solvent/Humidity Driven Stimuli Elastomer Actuation 30
Chapter 3 Experimental Section 32
3-1 Materials 32
3-2 Synthesis 32
3-2-1 Synthesis of bifunctional monomer BAHB 32
3-2-2 Synthesis of oligomer 35
3-3 Fabrication of LCEs based on photo patterning technique 37
3-3-1 Fabrication of polydomain LCE film 37
3-3-2 Fabrication of monodomain LCE 40
3-3-3 Fabrication of thermal tunable LCEs based on photo patterning technique 40
3-4 Analysis Apparatus 41
Chapter 4 Results and Discussion 43
4-1 1H-NMR of BAHB 43
4-2 Characterization of oligomer 1A 44
4-2-1 1H-NMR of oligomer 1A. 44
4-2-2 Molecular weight calculation of oligomer 1A by 1H-NMR 44
4-2-3 Molecular weight calculation of oligomer 1A by gel permeation chromatography (GPC) 46
4-2-4 Thermal properties of oligomer 1A 46
4-3 Characterization of LC mixture 49
4-3-1 Thermal properties 49
4-3-2 UV spectra of LC mixture 51
4-4 Thermal actuation of monodomain LCE 52
Schematic illustration of thermal tunable LCE 53
4-5 Characterization of LCE actuator 54
4-5-1 Actuation behavior of sample film 54
4-5-2 Fixing of highly ordered hinge 55
4-5-3 DSC analysis 56
4-6 Swelling ratio and gel fraction 57
Chapter 5 Conclusions 59
Chapter 6 References 60

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