完整後設資料紀錄
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dc.contributor.author戴興杰en_US
dc.contributor.author莊祚敏en_US
dc.date.accessioned2014-12-12T02:29:03Z-
dc.date.available2014-12-12T02:29:03Z-
dc.date.issued2001en_US
dc.identifier.urihttp://140.113.39.130/cdrfb3/record/nctu/#NT900500058en_US
dc.identifier.urihttp://hdl.handle.net/11536/69287-
dc.description.abstract誘電性液晶具有快速應答、廣視角、雙安定性、自發偶極與記憶性等優良的光學性質,但是誘電性液晶在顯示器的應用上,由於誘電性液晶需要使用表面安定技術(試片厚度小於2μm)將之解旋後方能達到最佳的光電效果,過於薄的試片厚度導致在大尺寸誘電性液晶顯示器製作時良率不佳,造成目前此種液晶材料的開發受到限制,因此如何建立一全新誘電性液晶排列之機制,且將之應用於間隙較厚之液晶元件上並仍具優良之光電性質即成為重要之課題。 本研究為誘電性液晶的缺點,改善誘電性液晶排列上之問題,故採用賓主系統並結合原位聚合法與光誘導排列法,利用分子設計合成出三系列共九個同時具有丙烯酸酯基與肉桂團基化合物。結構包括以長碳烷基為間距(其碳數n為8, 10, 12),液晶基為苯及聯苯,連接基為丙烯酸酯,末端不對稱基為含0~2個不對稱中心以及五個碳原子長的烷基鏈,以壓克力為高分子主鏈,肉桂團基為交聯基。 研究共分為三大部份 第一部份為含有壓克力與桂皮團基化合物的合成與熱性質探討。合成三系列如前述結構之側鏈高分子單體;液晶相行為經由熱微差掃描卡計、偏光顯微鏡以及粉末X-ray繞射加以鑑定液晶相的種類與排列結構,分別探討不同間距長度以及末端不對稱基對液晶行為之影響。結果顯示,所有的化合物中,除柔軟間距過短及缺乏不對稱中心之ACI812N及ACI1012N沒有液晶相,當增加末端基之不對稱中心個數與偶極矩時,其結晶點的溫度有下降之趨勢,而增廣其層列型液晶相之溫度範圍,在雙不對稱末端基的液晶分子中,可增加SC*相之熱安定性,溫度範圍可達約50℃且包含室溫。 第二部份為賓主型系統的排列特性之探討。將第一部份所合成之單體進行二步驟之光化學反應,可得側鏈型高分子以及交聯其肉桂團基。第一步驟是利用波長365nm的紫外光照射聚合;第二步驟是透過波長313nm的線性偏極紫外光曝照而得。並針對側鏈交聯高分子對賓主型液晶系統的排列行為加以討論。結果顯示,高秩序度之側鏈交聯型高分子,能誘導液晶分子垂直於線性偏極光之方向排列。 第三部份為賓主型系統的光電特性之探討。選擇具有寬廣SC*相之誘電性液晶(MD312C)作為主液晶,而以第一部份所合成之單體作為其賓液晶。賓主型液晶系統測量自發性極化量、應答時間及對比度等光電性質。並探討側鏈高分子之交聯密度對其光電性質的影響。結果顯示,在不減慢其應答速度下,高秩序度之側鏈交聯可增加自發極化量約10%左右、對比度約100%左右。 本研究已成功的合成出可光聚合及光交聯之化合物,透過高秩序度之側鏈交聯型賓主系統,在不影響誘電性液晶應答速度之情況下,增加其排列性質、自發極化量及對比度,提供一全新的誘導排列機制。zh_TW
dc.description.abstractFerroelectric liquid crystals (FLCs) have great electro-optical properties of fast response time (τ), large spontaneous polarization (Ps) value, high contrast ratio (gray-scale), wide view angle, bistable character, and memory effect. However, the drawbacks of FLC materials such as thin cell gap are impeded the application of display and other uses of electro-optical devices. In this work, we combine the advantages of guest-host system, in situ polymerization, and photoinduced reorientation to improve the drawbacks of FLCs. The monomers containing with acrylate and cinnamste groups were synthesized. The liquid crystal (LC) thermal properties were characterized by differential scanning calorimetry, optical polarizing microscopy, temperature-dependent power X-ray diffraction measurements. The detailed relationships between chemical structures and liquid crystalline behaviors were discussed. In the results, it shows that all of the compounds have LC behaviors, except ACI812N and ACI1012N. As the dipole moment of tails increases, the crystalline point decreases, then widen the range of smectic phase. In the case of two chiral centers, the SC* phase can be achieved about 50℃ (including room temperature). In the guest-host system, photoinduced reorientation can be achieved by ordered cross-type network via irradiated with 313nm linearly polarized ultraviolet light (LP-UV light). The ordered cross-type network can improve the electro-optical properties (higher spontaneous polarization value, constant response time, and higher contrast ratio) of the guest-host system. Furthermore, the cell gape of FLC display can be up to 5μm (potentially larger than 5μm). Upon irradiation, theses mixture-filled 5μm cells exhibit similar electro-optical properties as compared to those in the 2μm cells.en_US
dc.language.isozh_TWen_US
dc.subject誘電性液晶zh_TW
dc.subject賓主液晶系統zh_TW
dc.subject肉桂酸zh_TW
dc.subject線性偏極光zh_TW
dc.title原位聚合及光致排列誘電性液晶賓主型系統之研究zh_TW
dc.typeThesisen_US
dc.contributor.department應用化學系碩博士班zh_TW
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