- 學位論文
合成和探討旋光基烷鏈為支鏈和燕尾型態之T字型和桿狀液晶材料
Synthesis and Investigation of T-shaped and Rod-like Liquid Crystal Materials with Branched Alkyl Chain and Swallow-Tailed Chiral Groups
摘要
本研究分為三部分，分別探討T字型和桿狀乳酸衍生物藉由改變旋光末端烷鏈長度以及利用向列型液晶與T字型化合物摻混對於液晶相生成的影響。 第一、二部分的化合物液晶相和相轉移溫度都經由偏光紋理圖以及示差掃描熱量分析儀(DSC)來鑑定。在T字型化合物中，改變旋光末端烷鏈長度都只有SmA*相生成。而在桿狀化合物的旋光末端烷鏈長度超過2時，只有SmA*和SmC*的生成，旋光末端烷鏈長度不超過2時，皆有N*和TGBA*。相生成發現T字型和桿狀乳酸衍生物在旋光末端烷鏈為不對稱時，液晶相的範圍會增加，當m,n=(2,1)時液晶相範圍為最廣。 第三部分是探討混合液晶，使用T字型乳酸衍生物(TC31)與向列型液晶(TNCL3和5CB)混和，依不同的重量比例(1:5，1:3，1:1，2:1)以觀察液晶相的生成。 在液晶混合實驗中，在所有比例都發現膽固醇型液晶相生成。當混合比例為1:1和2:1中，可發現藍相的生成(Blue phase)。其中以比例為1:1時，藍相溫度範圍最廣，分別為3.3°C(TC31:TNCL3)和3.8°C(TC31:5CB)。
並列摘要
This study is divided into three parts, to study the mesomorphic properties of the T-shaped and rod-like liquid crystals with chiral swallow-tail derived from optically active (S)-lactic acid by changing chiral alkyl chain length. In addition, binary mixtures prepared from different rod- like liquid crystals are investigated. In the first part, the results of all of T-shaped compound Tmn with various alkyl chain length of swallow tail exhibit only SmA* mesophases. In the second part, when extending the alkyl chain length of chiral greater than 2, the N* and TGBA* phase formation is suppressed for rod-like series of compound 1Cmn. The third part of the works was to investigate the binary mixture materials. Thus, binary mixtures (TC31 and TNLC3, TC31 and 5CB) with the weight percentage ratios were prepared to investigate the formation of mesophases. Compound TC31 mixed with TNCL3 or 5CB causes the formation of frustrated BP and TGB phases. The wider temperature range of blue phase appeared at the 1:1 ratio of TC31 and 5CB about 3.8°C.