無機層狀材料奈米混成於高分子分散膽固醇液晶之光電性質探討

Study on Electro-optical Properties of Polymer Dispersed Cholesteric Liquid Crystals by Hybridizing Inorganic Layered Materials

楊凱勛(Kai-Hsun Yang)

指導教授 ： 蔡宗燕 ； 徐芝珊

中原大學/理學院/化學研究所/碩士(2015年)

https://doi.org/10.6840/cycu201500708

摘要

高分子分散液晶(PDLC)在光電領域中被廣泛的使用，例如智慧型薄膜、平板、軟性顯示器等。本研究利用膽固醇液晶(Cholesteric Liquid Crystal)混和光敏感高分子，製備出新型且具有熱致變色能力的高分子分散膽固醇液晶奈米複合材料(Polymer Dispersed Cholesteric Liquid Crystal, PDCLC/nanocomposite)，其組成包含向列型液晶E7、旋性劑S811、光敏感高分子NOA-65、無機層狀材料。無機層狀材料主要為天然黏土、苯環結構之電活性寡聚物(Pentamerous oligo-aniline, POA)改質型黏土、鋰鋁層狀雙氫氧化合物。實驗中利用廣角X光繞射光譜儀 (Wide Angle X-Ray Diffraction, XRD)、傅立葉轉換紅外線光譜儀(Fourier Transform Infrared, FTIR)及熱失重分析儀(Thermogravimetry Analyzer, TGA )、電子掃描式顯微鏡(Scanning Electron Microscope, SEM) 對有機化改質型黏土與鋰鋁層狀雙氫氧化物進行結構鑑定。將無機層狀材料以兩種不同製程(A製程：將無機層材膨潤於液晶、B製程：將無機層材膨潤於光敏感性高子)製備成PDCLC nanocomposites，利用偏振光光學顯微鏡(Polarizing Optical Micro-scope, POM)觀察膽固醇液晶於高分子系統中顯色型態，發現無機層狀材料的添加，在A製程中會影響膽固醇液晶的顯色型態。在外加交流電電場1 kHz下定溫量測閾值電壓、驅動電壓、對比度及瞬態時變之光學特性，發現驅動電壓降幅並沒有所預期的來的大，唯有苯胺寡聚體改質之黏土利用B製程所製備樣品(CL120-POA 0.5 % B)在相近螺距狀態下驅動電壓由124.39 Vrms降至115.62 Vrms。進一步利用掃描式電子顯微鏡觀察CL120-POA 0.5 % B高分子孔洞表面型態，發現其液晶滴粒徑最小。因此證明在B製程中改質型黏土的添加確實可增加高分子導電率，但受液晶滴粒徑的限制無法有效的降低驅動電壓。

關鍵字

無機層狀材料 ； 高分子分散膽固醇液晶 ； 電活性寡聚物 ； 奈米複合材料

並列摘要

Polymer-dispersed liquid crystals (PDLC) are widely used for electro-optic applications such as smart film, flat panel and flexible display etc. In this research work, a new kind of PDCLC/inorganic layered material nanocomposites has been synthesized by using thermochromic Polymer Dispersed Cholesteric Liquid Crystal (PDCLC), including nematic liquid crystal E7, chiral dopant S811, photocurable monomer NOA-65 and inorganic layered materials. Inorganic layered materials such as clay, modified clay, and Lithium Aluminum layered double hydroxide (LiAl LDH) were used. The morphology, thermal stability and organomodified inorganic layered materials identified by Wide Angle X-Ray Diffraction (WXRD), Scanning Electron Microscope (SEM), Thermogravimetry Analyzer (TGA), and Fourier Transform Infrared (FTIR). PDCLC/inorganic layered material nanocomposites were fabricated by two different methods (Method A: inorganic layered materials swelling in LC, Method B: inorganic layered materials swelling in photo curable monomer). The colour change of PDCLC nanocomposite observed by Polarizing Optical Microscope (POM). The colour of cholesteric liquid crystal in polymer system was affected by inorganic layered materials doped which were synthesized by Method A. Those samples threshold voltage, drive voltage, contrast ratio, response time will measure under 1 kHz AC electric field at constant temperature. The drive voltage were not lowering as expected but only one sample that doped modified clay- pentamerous oligo-aniline which was synthesized by Method B have lowered drive voltage at similar pitch, and voltage reduced from 124.39 Vrms to 115.62 Vrms. Further, morphology and polymer pore of PDCLC nanocomposites observed by SEM, the smallest liquid crystal droplet observed among all sample CL120-POA. Therefore, it is evidence that the CL120-POA doped by method B can raise conductivity of polymer, thus the small liquid crystal droplet effected the drive voltage.

並列關鍵字

Inorganic layered materials ； PDCLC ； electroactive oligomer ； nanocomposites

參考文獻

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