表面穩定鐵電型液晶(Surface-stabilized ferroelectric liquid crystal，縮寫為SSFLC)具有快速反應及雙穩態的特性，因此有許多學者投入相當之心力進行相關研究。而雖表面穩定鐵電型液晶有上述優點，但亦有些缺點，如雪弗龍(Chevron)結構之缺陷及液晶盒間距限制及其均勻度之製程難度等。一般而言，為達表面穩定鐵電型液晶雙穩態特性，製程上必須使液晶盒之上下玻璃基板間距小於2 m，因此該領域的研究受到相當的限制。此外，偶氮苯材料亦由於該材料對光的反應及其同素異構化所衍生出的特性，在近幾年來受到相當的重視，本論文利用摻雜偶氮苯材料於鐵電型液晶中，並探討其相關之光電特性，其中偶氮苯材料包含偶氮苯液晶及偶氮苯手性材料。 表面穩定鐵電型液晶其液晶分子在平行基板表面之平面上旋轉的範圍由其圓錐角大小決定，經實驗結果證明可利用摻雜偶氮苯材料改變表面穩定鐵電型液晶之圓錐角大小，並利用照射紫外光使偶氮苯材料處於電偶極矩較高的順式結構，該結構可加強表面穩定鐵電型液晶之穩態特性。為深入探討此穩態的機制，本論文分別將層列C型液晶及層列C*型液晶摻雜不同偶氮苯材料所得之表面穩定鐵電型液晶，探討照射紫外光前後該表面穩定鐵電型液晶之光電特性及相關機制。相信該穩態機制對表面穩定鐵電型液晶未來的發展有相當之助益。 ;Surface-stabilized ferroelectric liquid crystals (SSFLCs) possess their unique characteristics of fast response and bistability. Many scientists have been paying much attention to this research topic in recent decade. Although SSFLCs have the advantages mentioned above, some shortcomings, such as Chevron defect, horizontal defect, and the limitation of small cell gap and uniformity, should be considered. Generally speaking, to obtain the property of bistability, the cell gap of the SSFLC cell is limited to be smaller than 2 m. As a result, the cell fabrication processes are extremely difficult so that the researches in this field gradually decrease. The rotation range in the plane of the LC cell of SSFLC molecules is dependent on the cone angles of the FLCs. According to our experimental results, the cone angle of the FLCs can be modulated by doping azobenzene materials into smectic C / smectic C*, and by illuminating with UV light. Moreover, the stability of azobenzene-doped SSFLCs can be enhanced by illuminating with UV light to get cis-azobenzenes, having relatively high electric dipole moment. To establish the mechanism of the generation of the SSFFLC stability, the electro-optical properties of SSFLCs, prepared by the mixtures of various azobenzenes and smectic C / smectic C*, have been studied before and after been treated with UV illumination. Accordingly, we believe that such a novel approach can improve the developments of the SSFLC in LC technology.
