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研究生：	陳宥任 Chen, Yu-Jen
論文名稱：	寬波光子晶體薄膜之光聚合法製備及其光學特性探討 Fabrication and Optical Characterization of Broad-Band Photonic Films Induced via Photopolymerization
指導教授：	劉瑞祥 Liu, Jui-Hsiang
學位類別：	碩士 Master
系所名稱：	工學院 - 化學工程學系 Department of Chemical Engineering
論文出版年：	2016
畢業學年度：	104
語文別：	英文
論文頁數：	73
中文關鍵詞：	寬波段反射、光聚合、拓印、膽固醇液晶
外文關鍵詞：	broad band Bragg reflection, photopolymerization, imprinting, cholesteric liquid crystal
相關次數：	點閱：99 下載：1
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本研究以控制光聚合機制製程製備具有寬反射波段之膽固醇液晶拓印元件，一般而言，變溫光聚合過程或是加入光吸收染料皆可達到布拉格反射波段拓寬之目的。本研究在光聚合過程中，調控紫外光源強度和液晶元件的間距，使產生紫外光強度梯度並找尋最佳製程條件。高分子模板之拓印，是藉由聚合以向列型液晶nematic LC (HSG22200)、手性摻雜物 (CB15)、非手性的雙官能基單體4,4’-Bis ((6-acryloyloxy)hexyloxy)biphenyl (BHAB)以及光起始劑(Irgacure-184)之均勻混合物來製備，在光聚合過程中施以不同紫外光強度，影響到聚合之速率快慢進而使所拓印出之膽固醇螺旋結構有所變化，以致在同一液晶拓印元件內產生多種不同螺距，以擴寬反射波段。待溶劑洗滌步驟之後，透過所拓印之高分子模板並重新填入向列型液晶來誘導膽固醇液晶相。又，藉由堆疊兩不同反射波段之高分子模板，可成功製備寬反射波段液晶拓印元件。本研究中亦比較了本實驗之方法和固定紫外光強度聚合方法間的差異，探討布拉格光反射特性。反射光譜，是由光纖式UV-vis光譜儀來進行分析。

Fabrication of broadband cholesteric liquid crystal imprinted cell by controlling photopolymerization has been performed. The broad band Bragg reflection cholesteric liquid crystal cells have been achieved by using UV bleachable dye, temperature variance photopolymerization process, etc. In this study, imprinting and broadening of reflection band of cholesteric liquid crystal cells were achieved via controlling UV polymerization. Intensity gradient of UV light was achieved by adjusting the distance between UV lamp and the sample cell. Imprinted template was prepared by photopolymerization of mixed nematic LC (HSG22200), chiral dopant (CB15), bifunctional monomer, 4,4’-Bis((6-acryloyloxy) hexyloxy)biphenyl (BHAB), and photoinitiator (Irgacure-184). Intensity of UV light may affect the polymerization rate leads to the formation of imprinted helical construction with different pitches. Pitch gradient inside the systems usually broaden the reflection band of sample cells effectively. After polymerization, the residual liquid crystal mixture was then removed by using solvent. Refilling of nematic liquid crystal increases refractive indexes leads to the enhancement of reflection light of sample cells. Stacking of two imprinted cells with different pitches broadens reflection band effectively. In this study, comparison of this new designed process with traditional UV polymerization process was carried out. Spectral characterizations and optical reflection of sample cells were performed using fiber optic spectrometer.

Abstract	I
中文摘要	II
致謝	III
I. Introduction	1
1-1 Preface	1
1-2 Research Motivation	3
II. Literature Review	4
2-1 Introduction of Liquid Crystals	4
2-2 Classification of Liquid Crystals	6
2-2-1 Thermotropic Liquid Crystal	8
2-2-1-1 Nematic Liquid Crystal Phase (NLC)	9
2-2-1-2 Smectic Liquid Crystal Phase (SmLC)	10
2-2-1-3 Cholesteric Liquid Crystal Phase (ChLC)	11
2-2-2 Lyotropic Liquid Crystal	16
2-3 Anisotropic Properties of Liquid Crystals	17
2-3-1 Birefringence of Liquid Crystals	18
2-3-2 Influence of Temperature on Nematic Liquid Crystals	20
2-3-3 Dielectric Properties of Liquid Crystals	21
2-4 Polymer Stabilized Cholesteric Liquid Crystals	22
2-4-1 Selective Light Reflection and Optical Activity	24
2-4-2 Wide Reflection Band Devices- A Survey	25
2-4-2-1 Kinetics Control of Photopolymerization in Cholesteric Elastomer	25
2-4-2-2 Temperature Variance Photopolymerization	28
2-4-2-3 Thermal Diffusion of Glassy Cholesteric Oligomers	30
2-4-2-4 Reflection Band Broadening by Photo-racemization	32
2-4-2-5 Atmospheric Photopolymerization	33
2-4-2-6 Unsticking Technique	35
III. Experimental Section	37
3-1 Materials	37
3-2 Instruments	38
3-3 Experimental Process	39
3-3-1 Synthesis of Bifunctional Monomer	39
3-3-2 Fabrication of imprinted liquid crystal cell	40
3-3-3 Measurement of Selective Reflection Photonic Band Gap	45
3-3-4 Surface Morphology Analysis of Polymer Template	46
IV. Results and discussion	47
4-1 Characterization of the Synthesized Compounds	47
4-1-1 Structure Identification	47
4-1-2 Thermal Properties of BAHB	51
4-1-3 Optical Properties of BAHB	52
4-2 Characterization of ChLC Imprinting Cell	54
4-2-1 Components Analysis of ChLC Imprinting Cell	54
4-2-2 Optical Characterization of Imprinted Cell	55
4-2-3 Comparison of Normal Process and UV Gradient Process	58
4-2-4 Energy Effect on ChLC Imprinting Cell	60
4-2-5 Microstructure and Morphology of Imprinted Cells	63
4-3 Characterization of Stacked Cell	64
4-3-1 Optical Characterization of Stacked Cell	65
4-3-2 Swelling Effect of Stacked Cell	66
V. Conclusions	67
Rerferences	68

                                    

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校內：2018-07-01公開
校外：2018-07-01公開

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