本文選題：液體-液晶界面型傳感器 + 離子液體�。� 參考：《曲阜師范大學(xué)》2017年碩士論文

【摘要】：液體-液晶界面型傳感器通常利用表面活性劑分子與目標物在液體-液晶界面上發(fā)生相互作用進而誘導(dǎo)液晶分子的排列取向發(fā)生變化,從而實現(xiàn)對目標物的檢測。它具有操作更簡便、可實時檢測生物或者化學(xué)反應(yīng)的進程、更易于構(gòu)建陣列化和微型化的傳感器等優(yōu)勢,因此受到了廣泛的關(guān)注。但是目前,這類傳感器的相關(guān)研究大都局限于以水作為介質(zhì)、以傳統(tǒng)的表面活性劑作為修飾劑,難以滿足對目標物及生化事件檢測的越來越高的要求。因此,亟需尋找合適的非水溶劑以及設(shè)計開發(fā)結(jié)構(gòu)新穎的表面活性劑,用以構(gòu)建新型的液體-液晶界面?zhèn)鞲衅�。鑒于此,本論文著眼于以綠色溶劑—離子液體作為介質(zhì);同時設(shè)計合成各種結(jié)構(gòu)的表面活性劑(如刺激響應(yīng)性表面活性劑、表面活性離子液體和Gemini表面活性劑等),以之修飾液體-液晶界面,進而構(gòu)建新型液體-液晶界面?zhèn)鞲衅�。具體說來,本論文的主要內(nèi)容包括以下四個部分:第一章介紹了液晶界面型傳感器、表面活性劑和離子液體等方面的相關(guān)背景知識以及國內(nèi)外相關(guān)的研究現(xiàn)狀,并提出了本論文的研究思路。第二章合成了光響應(yīng)的偶氮苯類表面活性劑—4-乙基偶氮苯-4'-己氧基三甲基溴化銨(azoTAB),并用其作為修飾劑,以離子液體—硝酸乙銨(EAN)為介質(zhì),構(gòu)建了穩(wěn)定持久可逆的液體-液晶光響應(yīng)型界面。本章主要采用了偏光顯微鏡、紫外/可見/近紅外分光光度計等技術(shù)手段進行實驗研究。研究發(fā)現(xiàn),當azoTAB的濃度較高時,在紫外光和可見光的交替作用下,液晶的光學(xué)形貌和液晶分子在液-液界面上的排列方式分別發(fā)生了由暗到亮及由垂直到平行的交替變化。這主要是由于偶氮苯類表面活性劑分子的構(gòu)型經(jīng)歷了順反異構(gòu)的可逆變化。研究發(fā)現(xiàn),相比于水-液晶界面,EAN幾乎不蒸發(fā)的特性使得液晶的光學(xué)圖片更加穩(wěn)定,至少可在一個月內(nèi)不用更換溶劑,并可實現(xiàn)多次光控可逆循環(huán),因此離子液體-液晶界面具有更好的可控性、穩(wěn)定性和重現(xiàn)性。另外,將少量EAN作為電解質(zhì)添加到水溶液-液晶界面上,得到了與添加無機鹽電解質(zhì)(例如NaCl)類似的結(jié)果,即導(dǎo)致液晶光學(xué)形貌變化的臨界濃度降低,主要原因是電解質(zhì)屏蔽了表面活性劑頭基之間的靜電斥力;但當加入大量的EAN時改變了溶劑性質(zhì),致使臨界濃度增大。第三章研究了一系列結(jié)構(gòu)不同的咪唑類表面活性離子液體分別修飾水溶液-液晶界面和離子液體-液晶界面時對液晶分子排列取向的影響。本章合成了三種短鏈的離子液體—硝酸乙銨(EAN)、硝酸丙銨(PAN)、硝酸丁銨(BAN)和八種咪唑類表面活性離子液體(IM-SAILs),包括單鏈IM-SAILs:1-十二烷基-3-甲基咪唑溴([C12mim]Br)、1-十四烷基-3-甲基咪唑溴([C14mim]Br)、1-十六烷基-3-甲基咪唑溴([C16mim]Br)、1-十二烷基-3-甲基咪唑水楊酸鹽([C12mim]Sal)、1-十二烷基-3-甲基咪唑3-羥基-2-萘酸鹽([C12mim]HNC)、1-十二烷基-3-甲基咪唑肉桂酸鹽([C12mim]CA)和1-十二烷基-3-甲基咪唑?qū)αu基肉桂酸鹽([C12mim]PCA)以及雙子IM-SAIL:二亞甲基-1,2-雙(3-十二烷基咪唑)溴([C12-2-C12im]Br2)。主要采用偏光顯微鏡觀察了烷基鏈長、鏈數(shù)及反離子不同的IM-SAILs對液晶偏光響應(yīng)的影響。發(fā)現(xiàn)無論是在水溶液-液晶界面還是EAN-液晶界面,隨著[Cnmim]Br(n=12-16)烷基鏈的增長,使臨界濃度逐漸減小;雙烷基鏈[C12-2-C12im]Br2的臨界濃度明顯低于單鏈[C12mim]Br;反離子的不同(Br-和各種芳香陰離子)卻對液晶分子在界面上的排列取向影響很小。另外,相比于水溶液-液晶界面,離子液體(EAN、PAN或BAN)-液晶界面擁有更高的臨界濃度和更穩(wěn)定的液晶光學(xué)形貌,這主要歸因于溶劑內(nèi)部結(jié)構(gòu)的差異。第四章主要采用偏光顯微鏡研究了兩類結(jié)構(gòu)不同的陽離子型Gemini表面活性劑修飾到液體-液晶界面時引起液晶排列取向的變化情況。設(shè)計合成了季銨鹽型的Gemini表面活性劑:溴化二亞甲基-1,2-雙烷基季銨鹽(m-2-n,m=12,14,16;n=12,10,8;m+n=24)以及咪唑類Gemini表面活性離子液體:二亞甲基-1,2-雙(3-烷基咪唑)溴([Cn-s-Cnim]Br2,s=2,n=6,8,10,12,16)和s亞甲基-1,s-雙(3-十二烷基咪唑)溴([Cn-s-Cnim]Br2,n=12,s=2,4,6,10)。研究發(fā)現(xiàn),咪唑類Gemini表面活性離子液體的雙烷基鏈越長,誘導(dǎo)臨界濃度越低。隨著咪唑類Gemini表面活性離子液體連接基的增長,其臨界濃度也隨之增大。對稱性不同、但雙烷基鏈長總和相等的三種季銨鹽型的Gemini表面活性劑具有相近的臨界濃度。以咪唑為頭基的[C12-2-C12im]Br2的臨界濃度比季銨陽離子為頭基的12-2-12明顯低。說明對Gemini表面活性劑來說,雙烷基鏈總鏈長、連接基長度以及頭基類型的改變都會誘導(dǎo)液晶分子在液體-液晶界面上的排列取向發(fā)生變化。以上研究工作表明,離子液體和新型表面活性劑在液體-液晶傳感器領(lǐng)域中具有很好的應(yīng)用前景。本論文為拓寬液體-液晶界面?zhèn)鞲衅鞯臉?gòu)建方法以及提升其檢測性能奠定了堅實的理論基礎(chǔ)。
[Abstract]:Liquid liquid crystal interface sensor usually uses the interaction of surfactant molecules and objects on liquid crystal interface and then induces the alignment of liquid crystal molecules to change the alignment of liquid crystal molecules, thus realizing the detection of the target. It is easier to operate, can detect the process of biological or chemical reaction in real time, and is easier to build the array. However, most of the related research of this kind of sensor is limited to water as the medium and the traditional surface active agent as a modifier, so it is difficult to meet the higher requirements for the detection of targets and biochemical events. Therefore, it is urgent to find a suitable non water soluble solution. The agent and the design and development of a novel surface active agent are used to construct a new liquid liquid crystal interface sensor. In view of this, this paper focuses on the use of green solvents, ionic liquids as medium, and the design of synthetic surfactants (such as irritation surfactants, surface active ionic liquids and Gemini surface activity). The main contents of this paper include the following four parts: the first chapter introduces the related background knowledge of the liquid crystal interface sensor, the surface active agent and the ionic liquid, as well as the related research status at home and abroad, and proposes the relevant research status at home and abroad. The second chapter synthesizes the photoresponse azobenzene surface active agent, 4- ethyl azobenzene -4'- dioxy ammonium bromide (azoTAB), and uses it as a modifier, and uses the ionic liquid - ammonium nitrate (EAN) as the medium to build a stable and durable liquid liquid crystal light response interface. This chapter is mainly used in this chapter. It is found that the optical morphology of the liquid crystal and the arrangement of liquid crystal molecules on the liquid liquid interface occur from dark to bright and from perpendicular to parallel to the liquid liquid interface, when the concentration of azoTAB is high, and when the concentration of ultraviolet and visible light is high. It is mainly because the configuration of azobenzene surfactant molecules has undergone a reversible change in the CIS and trans isomerization. It is found that the properties of EAN almost do not evaporate in comparison with the water liquid crystal interface, which makes the optical images of the liquid crystal more stable, at least one month without replacing the solvent, and thus can achieve multiple optical control reversible cycles. The ionic liquid - liquid crystal interface has better controllability, stability and reproducibility. In addition, a small amount of EAN as an electrolyte is added to the liquid liquid crystal interface. The result is similar to the addition of inorganic salt electrolytes (such as NaCl), that is, the critical concentration of the changes in the optical morphology of the liquid crystal is reduced, mainly because the electrolyte shields the surface. The electrostatic repulsion between the active agent head groups; but when a large amount of EAN is added, the solvent properties are changed and the critical concentration increases. The third chapter studies the influence of a series of imidazole surface active ionic liquids on the alignment of liquid crystal molecules with liquid crystal interface and ionic liquid liquid crystal interface. Three kinds of short chain ionic liquids - ammonium nitrate (EAN), ammonium nitrate (PAN), ammonium nitrate (BAN) and eight imidazole surface active ionic liquids (IM-SAILs), including single chain IM-SAILs:1- twelve alkyl -3- methyl imidazolium bromide ([C12mim]Br), 1- fourteen alkyl -3- methyl imidazolium bromide ([C14mim]Br), 1- sixteen alkyl -3- methyl imidazolium bromide (1), 1 - twelve alkyl -3- methidazolicsalicylate ([C12mim]Sal), 1- twelve alkyl -3- methyl imidazole 3- hydroxyl -2- naphthalate ([C12mim]HNC), 1- twelve alkyl -3- methyl imidazole cinnamate ([C12mim]CA) and 1- twelve alkyl -3- methylimidazole against hydroxyl cinnamate, and Gemini two methylene glycol (twelve alkyl imidazole) Bromine ([C12-2-C12im]Br2). The effect of alkyl chain length, chain number and different IM-SAILs on the response of liquid crystal polarization is observed mainly by polarizing microscope. It is found that the critical concentration gradually decreases with the increase of [Cnmim]Br (n=12-16) alkyl chain in aqueous solution liquid crystal interface or EAN- liquid crystal interface; the dialkyl chain [C12-2-C12im]Br2 is gradually reduced. The critical concentration is obviously lower than the single strand [C12mim]Br, but the difference of the reverse ion (Br- and various aromatic anions) has little influence on the arrangement orientation of the liquid crystal molecules on the interface. In addition, the ionic liquid (EAN, PAN or BAN) - liquid crystal interface has higher critical concentration and a more stable liquid crystal optical morphology than the aqueous liquid crystal interface. In the fourth chapter, the fourth chapter mainly uses polarizing microscope to study the changes in the alignment of liquid crystals when the two kinds of cationic surfactant of different structures are modified to liquid crystal interface. A quaternary ammonium salt Gemini surfactant is designed and synthesized, and two methylene -1,2- dialkyl quaternary ammonium bromide is prepared. Salt (m-2-n, m=12,14,16; n=12,10,8; m+n=24) and imidazole Gemini surface active ionic liquids: two methylene -1,2- double (3- alkyl imidazole) bromine ([Cn-s-Cnim]Br2, s=2, n=6,8,10,12,16) and s methylene -1. The longer the base chain is, the lower the critical concentration is. With the increase of the imidazole Gemini surface active ionic liquid junction, the critical concentration also increases. The symmetry is different, but the three quaternary ammonium salt type Gemini surfactants with equal dialkyl chain length have similar critical concentration. The critical [C12-2-C12im]Br2 critical to imidazole is critical. The concentration ratio of quaternary ammonium cation to the head based 12-2-12 is significantly lower. It shows that the total chain length of the alkyl chain, the length of the connective group and the change of the head type will induce the changes in the alignment of the liquid crystal molecules at the liquid crystal interface for the Gemini surfactants. The above research shows that the ionic liquid and the new surfactant are in the liquid. It has a good application prospect in the field of liquid crystal sensor. This paper lays a solid theoretical foundation for widening the method of constructing liquid crystal interface sensor and improving its detection performance.
【學(xué)位授予單位】：曲阜師范大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O645.1;TP212

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