- 學位論文
側鏈鐵電性液晶聚環氧丙烷之合成及性質研究（IX）
Studies on the Synthesis and Properties of Ferroelectric Side Chain Liquid Crystalline Polyoxetane(IX)
摘要
本研究之目的在合成三系列具旋光性的側鏈型鐵電性液晶。三系列均以環氧丙烷（HMMO）當作主鏈，以寡氧乙烯基（oligooxyethylene）為柔軟間距，末端連接基為醚鍵(-O-)；末端旋光基為含1個旋光中心之甲基丁烷的液晶聚合物。三系列液晶單體皆以BF3．OEt2作為起始劑進行開環聚合合成聚合物。此三系列的液晶單體及其聚合物以FTIR及NMR進行分析確認結構，再以微差掃描卡計（DSC）及偏光顯微鏡(POM)分析鑑定識別所含液晶相種類及溫度範圍，最後利用自動極化裝置[APT(II)]測其自發極化值(Ps)及應答時間(τ)。 研究結果發現：在單體時，隨著寡氧乙烯基間隔鏈的增加而有降低熔點的趨勢。所有液晶聚合物皆為雙變式液晶，第一系列將苯環上氫以氟原子取代，造成液晶基排列規則性降低，而呈現出旋光層列C型(Sc*)液晶相。第二系列以萘環為主要液晶基團，將會降低液晶呈現溫度且減少其液晶相的變化，及不易呈現出旋光層列C型(Sc*)液晶相，只出現低黏度之旋光向列型(N*)液晶相。第三系列為具有四苯環液晶基之剛硬結構，不僅具有旋光層列C型(Sc*)液晶相，且自發極化值最大可達到112.36 nC/cm2。三系列液晶聚合物，除了第二系列液晶聚合物外，其餘皆呈現出較寬廣的旋光層列C相，其中第三系列之旋光層列C相溫度範圍更可達80℃以上。
並列摘要
Three series of novel ferroelectric liquid crystalline (FLC) monomers and their corresponding side chain polymers were synthesized in this study. Three series of polymers were polymerized containing the same polyoxetane as the backbone, oligooxyethylene as the flexible spacer, and ether group as the terminal linkage. The chiral moiety with one asymmetric carbons on the 2(s)-methylbutane was used. Three series of novel polyoxetanes were prepared from those above FLC monomers by ring-opening polymerization using BF3．OEt2, as an initiator. These obtained monomers and polymers were characterized by using optical polarized microscope with a heating stage, differential scanning calorimetry (DSC), FT-IR, NMR, and APT(II). The following results were obtained. The melting points of the monomers decrease with increasing the length of the flexible spacer. All the polymers were identified as the enantropic liquid crystals. The first series of monomers containing a phenyl ring substituted with fluorine tends to form the lower ordered liquid crystalline phases. The chiral smectic C phase is exhibited. The second series of monomers containing a naphthalene ring into the mesogen core would decrease the tendency of the formation of chiral smectic C phase. However, the lower viscosity chiral nematic phase is exhibited. The third series of monomers containing a rigid mesogen with four phenyl rings tends to form the chiral smectic C phase and the high spontaneous polarization value (~112.36 nC/cm2). All of the synthesized polymers, except the second series of polymers, exhibited wide temperature range of chiral smectic C phase. Especially, the temperaturec range of chiral smectic C phase of the third series are over the 80℃.