發(fā)布時間：2018-11-10 12:49

【摘要】：盤狀液晶分子因?yàn)槿嵝詡?cè)鏈和平面對稱結(jié)構(gòu)的剛性核共同作用而展現(xiàn)出液晶性能。但是柔性側(cè)鏈過多或過長、剛性中心核不規(guī)則、乃至分子是多聚體或高分子等原因都影響了盤狀液晶分子的自組裝性能。通過摻雜其他分子進(jìn)行誘導(dǎo)可以改善分子的自組裝性能,例如通過摻雜富電子的2,4,7-三硝基芴酮(TNF)與盤狀液晶形成電荷轉(zhuǎn)移復(fù)合物就是一種常見的方法。以往在研究烷氧基苯并菲(HAT)與TNF復(fù)合的工作中,關(guān)于兩者的作用模式存在爭議。Boden等人認(rèn)為TNF是以ABABAB…型摻雜在HAT分子之間的;而Mulder等人則認(rèn)為TNF只是分布在由HAT分子堆疊的柱狀組裝體之間。本論文第一部分即深入探究了烷氧基苯并菲(HAT)與TNF復(fù)合后的作用模式;此外,為了擴(kuò)展研究內(nèi)容的寬度,論文還設(shè)計(jì)合成了兩類新型苯并菲四聚體,并探討了其與TNF復(fù)合后的主客體性質(zhì)和液晶性能。主要內(nèi)容包括:一、TNF與五烷氧基苯并菲(HAT5)復(fù)合物液晶性能的研究。HAT5是典型的盤狀液晶分子,可自組裝成六方柱狀相。通過添加TNF分子形成電子給體-受體復(fù)合物后,HAT5液晶相溫度區(qū)間由原來的70℃-115℃擴(kuò)寬到0℃-250℃,極大改善了其液晶的穩(wěn)定性。X-小角散射實(shí)驗(yàn)發(fā)現(xiàn),隨著TNF摻雜濃度的增加,HAT5組裝結(jié)構(gòu)中的六方晶胞參數(shù)在減小,而兩個柱狀組裝體之間的距離仍然是一個定值(0.34 nm)。這表明TNF分子并不是分布在HAT5堆疊的柱狀組裝體之間的位置,而是通過電荷轉(zhuǎn)移作用位于兩個HAT5分子之間,形成了ABABAB…型結(jié)構(gòu)。顯微鏡測試結(jié)果也佐證了這一點(diǎn),并得出二者的最佳復(fù)合比是2:3(HAT5:TNF),當(dāng)二者比例達(dá)到1:1時,TNF達(dá)到飽和狀態(tài)。二、TNF和苯并菲四聚體絡(luò)合的主客體性質(zhì)和液晶性能研究。我們設(shè)計(jì)合成了兩種新型苯并菲四聚體衍生物,分別是以柱[5]芳烴為中心體的苯并菲四聚體(4HAT-P5A)和以四苯乙烯為中心體的苯并菲四聚體(4HAT5-TPE)。通過核磁共振和可見-紫外光譜測試表明,兩種苯并菲四聚體分別與TNF分子形成了電子給體-受體絡(luò)合物。通過核磁滴定研究了主客體之間的絡(luò)合比和絡(luò)合常數(shù),發(fā)現(xiàn)溶液中兩種絡(luò)合物主客體的絡(luò)合比均為1:2,絡(luò)合常數(shù)4HTA-P5A與TNF的Ka=0.215×104 M-1,4HTA-TPE與TNF的Ka=8.807×104 M-1。進(jìn)一步我們研究了兩種苯并菲四聚體的液晶性質(zhì)以及TNF摻雜后的誘導(dǎo)作用。結(jié)果發(fā)現(xiàn),單獨(dú)的苯并菲四聚體4HTA-P5A或4HTA-TPE均不能形成液晶態(tài);在加入TNF誘導(dǎo)后,4HTA-P5A仍然沒有液晶性質(zhì),而4HTA-TPE則表現(xiàn)出液晶性質(zhì),從常溫到107℃出現(xiàn)柱狀相液晶態(tài)。通過4HTA-TPE和TNF的二組分相圖,得出了固態(tài)下二個化合物最佳的復(fù)合比例為1:3,這與HAT5和TNF最佳復(fù)合比是2:3是吻合的。這些研究工作擴(kuò)展了苯并菲低聚物的研究領(lǐng)域,并有助于更深入了解電荷轉(zhuǎn)移復(fù)合物的液晶行為,便于更好的設(shè)計(jì)和制備性能優(yōu)良的液晶材料。
[Abstract]:Disk liquid crystal molecules exhibit liquid crystal properties due to the interaction of flexible side chains and rigid nuclei of planar symmetric structures. However, excessive or long flexible side chains, irregular rigid center nuclei and even polymer molecules affect the self-assembly performance of disk-like liquid crystal molecules. The self-assembly properties of the molecules can be improved by doping other molecules. For example, it is a common method to form charge-transfer complexes between (TNF) and disk liquid crystals by doping the electron-rich 2O4-7-trinitrofluorenone (TNF). In the past studies on the combination of alkoxy benzophenanthrene (HAT) and TNF, there has been a controversy about the mode of their action. Boden et al believe that TNF is based on ABABAB. Mulder et al think that TNF is only distributed between columnar assemblies stacked by HAT molecules. In the first part of this thesis, the interaction mode of alkoxy phenanthrene (HAT) and TNF was studied. In addition, in order to expand the width of the study, two new types of benzophenanthrene tetramer were designed and synthesized, and the host and guest properties and liquid crystal properties were discussed. The main contents are as follows: first, the liquid crystal properties of TNF / HAT5 complexes. HAT5 is a typical disk-like liquid crystal molecule, which can self-assemble into hexagonal columnar phase. By adding TNF molecule to form electron donor-receptor complex, the temperature range of HAT5 liquid crystal phase was widened from 70 鈩，

本文編號：2322513