高分子分散液晶-黏土奈米複材膜之製備與光電性質研究

Studies on the Preparation and Electro–Optical Properties for Polymer Dispersed Liquid Crystal/Clay Nanocomposites

張雲閔(Yun-Min Chang)

指導教授 ： 蔡宗燕

中原大學/理學院/化學系/碩士(2006年)

https://doi.org/10.6840/cycu200600679

摘要

本研究所使用無機層狀黏土為蒙脫土(Montmorillonite)，其本身結構為多層片狀堆疊成顆粒，層與層之間靠著離子鍵結力緊密結合，隨後選擇具有環狀結構且為多長碳鏈分子具親油性的改質劑(C11Z-CN)作為分子設計之界面活性劑，藉此與蒙脫土層間鈉離子進行陽離子置換反應，增加與有機相的相容性，實驗中利用廣角X光繞射光譜儀(XRD)、傅立葉紅外線光譜儀(FT-IR) 及熱重分析儀(TGA)對親有機化改質前後黏土的結構鑑定；此外，本論文中提出一新穎向列型液晶-奈米級蒙脫土的有機-無機奈米級複合材料，以微差掃描式分析儀(DSC)、偏光顯微鏡(POM)及變溫X光繞射光譜儀(XRD)探討摻雜蒙脫土於液晶中對於液晶排列位向秩序和結晶性的影響；接著，研究摻雜蒙脫土於水平排列液晶盒中，在外加直流或交流偏壓下，量測閾值電壓、驅動電壓、時變光學特性及觀察離子電荷之電光效應變化；最後，我們亦對於摻雜蒙脫土於液晶及單體前驅物中，利用光聚合法造成的相分離製成高分子分散液晶做研究，實驗中，利用紫外光曝光，由偏光顯微鏡(POM)觀察液晶的相型態，單道二極體雷射量測不同曝光光強及頻率下之交流偏壓；另外，針對全像光學做研究，利用兩道同調氬離子雷射干涉場曝光，探討不同入射角度、雷射光源光強和摻雜蒙脫土含量對於繞射效率變化，相形態學及其微結構。

關鍵字

高分子分散液晶 ； 蒙脫土 ； 奈米級複合材料

並列摘要

In this study, we applied the natural clay mineral, Montmorillonite, which aspect ratio is about 100 ~ 150 with the thickness of approximately 1 nm. The interaction between the gallery of clay is ionic bonds, which construct the layer stacking together to form a micrometer particle. The modified agent, 2-undecyl-1H-imidazole-1-propiononitrile, C11Z-CN, which is a carbon long chain with the cycloalkenes, was intercalated into the clay layers and increased the compatibility of the interface between the clay and liquid crystal. The properties were characterized by XRD, FT-IR, TGA, DSC and POM. In this work, we reported a new type of organic–inorganic hybrid nanocomposite, comprised by the nematic liquid-crystal and nanoscale montmorillonite. The electro-optical effects were discussed such as the voltage- transmittance, voltage-capacitance and time-transmittance curves, which explain the charge-retention effect under the application of dc bias voltage in antiparallel-aligned cells. Polymer dispersed liquid crystal (PDLC) doped with clay, which were fabricated by photo-polymerization with liquid crystal and monomers under UV-curing, characterized by different curing power and frequency under ac bias voltage for the electro-optical properties. We also studied on the holography of PDLC doped with clay. There are two coherent Ar+ laser interfering on the sample to form the interference field of the spatially periodic distribution. The effects of the incident writing angles, light intensity of incident laser beams and doped the small amount of clay on the diffraction efficiencies and morphology were investigated.

並列關鍵字

Nanocomposite ； Polymer Dispersed Liquid Crystal ； Montmorillonite

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