【作者】 刘方明；

【导师】 王力彦；

【作者基本信息】 吉林大学 ， 高分子化学与物理， 2014， 博士

【摘要】 刺激响应材料能够在受到外界刺激时产生自身性质的改变。多种刺激手段可以用来控制刺激响应材料的性能，包括电压、光、pH、温度、化学添加剂和外力作用等等。我们知道酰胺基团作为天然肽和蛋白的骨干结构而普遍存在于自然界中。由于其是良好的氢键给受体以及N上孤对电子的离域导致的部分双键性质，其在制备刺激响应材料中有独特的优势。在本文中，我们设计合成了一些酰胺化合物，并用其制备了刺激响应的单层膜、溶液、胶束和凝胶。取得的研究结果包括以下三个方面：(1)我们设计合成了含有N,N-双取代酰胺结构的硫辛酸衍生物脯氨醇硫辛酰胺(1a)，并用其在金表面制备自组装单分子膜(SAMs)，得到了溶剂响应性的SAM-1a，其在用乙醇和环己烷交替处理过后表面接触角呈现在约40°和59°往复变化；我们用核磁研究了1a的模型分子脯氨醇戊酰胺(1b)在乙醇和环己烷中的构象变化，这从构象上解释了SAM-1a在用乙醇和环己烷分别处理以后表面水接触角的变化。我们分别合成了具有N-单取代酰胺结构的N-羟乙基硫辛酰胺(2a)和具有N,N-双取代酰胺结构的N-甲基-N-羟乙基硫辛酰胺(2b)，用它们分别制备了自组装单分子膜SAM-2a和SAM-2b，并对比了它们表面的溶剂响应性；结果说明，N,N-双取代是制备溶剂响应性酰胺表面的基本条件。另外合成了不同长度烷基链的N,N-双取代酰胺硫辛酸衍生物，用它们制备得到的SAMs表现出不同的水接触角响应范围。(2)参照热响应聚合物的结构，我们设计合成了具有热响应性质的酰胺小分子N-正丙基丙酰胺(nPPAm)、N-仲丁基丙酰胺(sBPAm)和N-甲基-N-正丁基丙酰胺(MBPAm)，它们的水溶液在环境温度超过其浊点时发生相分离。我们绘制了酰胺-水体系的相图。其中nPPAm和MBPAm的低临界溶解温度(LCST)分别为19.7°C和33.9°C。通过引入手性基团，我们得到了具有温敏性质的手性酰胺小分子N-甲基-N-(S)-仲丁基丙酰胺(M(S)sBPAm)、脯氨醇戊酰胺((S)PPAm)、N-丁酰基-(S)-脯氨酸甲酯(B(S)PME)、N-((R)-1-羟甲基丙基)戊酰胺((R)HMPPtAm)和N-((R)-1-(甲氧基甲基)丙基)丁酰胺((R)MMPBAm)，并绘制了它们和水二元体系的相图；其中，M(S)sBPAm、(S)PPAm和B(S)PME的LCST分别为49.7°C、62.4°C和75.7°C。(3)我们设计合成了一系列含有寡聚(N-甲基甘氨酸)结构的两亲性分子N-十二烷基-N-甲基-2-(N-甲基-2-(N-甲基乙酰胺基)乙酰胺基)乙酰胺(C12A3)、N-十四烷基-N-甲基-2-(N-甲基-2-(N-甲基乙酰胺基)乙酰胺基)乙酰胺(C14A3)、N-十六烷基-N-甲基-2-(N-甲基-2-(N-甲基乙酰胺基)乙酰胺基)乙酰胺(C16A3)、N-十八烷基-N-甲基-2-(N-甲基-2-(N-甲基乙酰胺基)乙酰胺基)乙酰胺(C18A3)。其中，C12A3和C14A3在水溶液中自组装形成胶束，临界胶束浓度(CMC)分别为0.15mM和0.01mM；并且，该胶束具有热响应性质，当温度升高到胶束溶液的浊点，溶液出现浑浊，我们用紫外光谱仪表征了出现浑浊时的温度即浊点，它们水溶液的LCST分别为79.5°C和61.2°C。我们研究了C12A3的热响应胶束的在浊点萃取上的应用，在胶束水溶液中加入污染物尼罗红后，将溶液升温使其相分离，可以明显的看到尼罗红被富集到富胶束相；通过荧光光谱可以看到稀相中的荧光强度明显下降，而浓相中的荧光强度大幅度上升。C16A3和C18A3分子则显示热响应的凝胶性质，它们的水溶液具有双温度响应性，可实现“凝胶‐溶胶‐乳浊液”三态之间的可逆转换，在浓度为50mM时，C16A3水溶液的凝胶温度(Tgel)和浊点(TCP)分别为22.6°C和51.0°C，而C18A3水溶液的Tgel和TCP分别为38.0°C和39.9°C。更多还原

【Abstract】 Stimuli-responsive materials can alter their properties in response to changes inthe environment or an external stimulus. Currently, a lot of stimuli are utilized tocontrol properties including electrical potential, light, pH, temperature, chemicals, andmechanical forces. We know that amide bond is widespread in nature as the backboneof peptides and proteins. Amide group is a good hydrogen bond donor and accepter,and significant delocalisation of the lone pair of electrons on the nitrogen atom givesthe group a partial double bond character, which make it a good choice for preparationof stimuli-responsive materials. In this paper, we designed and synthesized severalamide compounds, and investigated their stimuli-responsiveness. Some creativeresults are described in the following paragraphs.(1) We have designed and synthesized a dithiooctanoic acid derivative bearingN,N-disubstituted amide groups, DL-N-(6,8-dithiooctanoyl)-L-prolinol (1a), and usedit to fabricate self-assembled monolayers (SAMs) on gold surface, resulting in asolvent-responsive surface SAM-1a. The film showed reversible changes inwettability, which was indicated by surface contact angle switching between40°and59°upon alternating treatments with ethanol and cyclohexane. NMR experimentalresults of a model molecule, N-pentanoyl-L-prolinol (1b), suggests that thesolvent-responsive wettability of the SAMs could be related with the changes in therelative populations of two stereoisomers of amide. Then, we synthesized aN-monosubstituted amide, N-hydroxyethyl-6,8-dithiooctanamide (2a), and aN,N-disubstituted amide, N-hydroxyethyl-N-methyl-6,8-dithiooctanamide (2b), andused them to fabricated SAM-2a and SAM-2b, respectively. Comparison of theirsolvent-responsiveness confirmed that N,N-disubstitution was essential to obtain a stimuli-responsive surface. Further, we synthesized N,N-disubstituted dithiooctanoicacid derivatives with different alkyl chain lengths, and the SAMs fabricated fromthem performed different response ranges of the contact angle.(2) According to the structure of thermo-responsive amide polymers, wedesigned and synthesized three amide-based thermo-responsive molecules,N-propylpropionamide (nPPAm), N-sec-butylpropionamide (sBPAm) andN-butyl-N-methylpropionamide (MBPAm). Their aqueous solutions undergo phaseseparation when the ambient temperature exceeds their cloud points. We draw theirphase diagrams of amide/water systems, in which the lower critical solutiontemperature (LCST) of nPPAm and MBPAm were indicated as19.7°C and33.9°C,respectively. By introducing chiral groups, several chiral amide molecules, withthermo-responsive character, were obtained, including (S)-N-sec-butyl-N-methylpropionamide (M(S)sBPAm), N-pentanoyl-L-prolinol ((S)PPAm), N-pentanoyl-(S)-proline methyl ester (B(S)PME), N-((R)-1-hydroxypropyl)pentanamide((R)HMPPtAm), and N-((R)-1-(methoxymethyl)propyl)butyramide ((R)MMPBAm).Their phase diagrams were drawn, and the LCSTs of M(S)sBPAm,(S)PPAm andB(S)PME were49.7°C,62.4°C and75.7°C, respectively.(3) We designed and synthesized a number of oligo(N-methylglycine))-bearingamphiphilic molecules, N-dodecyl-N-methyl-2-(N-methyl-2-(N-methylacetamido)acetamido)acetamide (C12A3), N-tetradecyl-N-methyl-2-(N-methyl-2-(N-methyl-acetamido)acetamido)acetamide (C14A3), N-hexadecyl-N-methyl-2-(N-methyl-2-(N-methylacetamido)acetamido)acetamide (C16A3), N-octadecyl-N-methyl-2-(N-methyl-2-(N-methylacetamido)acetamido)acetamide(C18A3). C12A3and C14A3canself-assemble into micelle in water, with critical micelle concentration (CMC) of0.15mM and0.01mM, respectively. When environment temperature rises to someextent, the micellar solution becomes turbid, which is characterized by UV-visspectrometer. The LCSTs for C12A3and C14A3are79.5°C and61.2°C, respectively.We studied the application of thermo-responsive micelles of C12A3in cloud pointextraction. After adding Nile Red as pollutants, the micelle solution separated into two phases at the temperature above the cloud point. It can be seen clearly that the Nilered is enriched into the micelle-rich phase, which is also confirmed by a decrease offluorescence intensity for micelle-lean phase and a significant increase offluorescence intensity for micelle-rich phase. C16A3and C18A3can formthermo-responsive hydrogel, which have dual temperature-response, and a reversiblesol-gel-emulsion transition can be achieved. At the concentration of50mM, the geltemperature (Tgel) and cloud point (TCP) for C16A3was22.6°C and51.0°C,respectively; and the Tgeland TCPfor C18A3were38.0°C and39.9°C.更多还原