脂肪酰谷氨酸与小分子有机凝胶

研究了脂肪酰谷氨酸作为凝胶因子在不同有机溶剂中的成胶性能。结果表明,小分子有机凝胶的形成及其稳定性与有机溶剂种类、凝胶因子浓度和凝胶因子中碳链长度密切相关。FT-IR表明,凝胶因子在有机溶剂中是通过氢键等非共价力相互作用而聚集、自我组装形成凝胶。利用光学显微镜观察发现,凝胶因子在不同有机溶剂中形成凝胶的微观结构不同。     

N-硬脂酰-L-谷氨酸及其乙酯衍生物的合成与成胶性质研究

研究了N-硬脂酰-L-谷氨酸(C18-GIu)——一个具有多个氢键位点的有机胶凝剂分子及其乙酯(C18-GIu-2ES)衍生物的合成与成胶性质．文献报道的合成方法是将硬脂酰氯滴加到L-谷氨酸钠的丙酮与水的混合溶液中,但我们的多次实验结果表明该合成方法的可操作性比较差,究其原因主要在于：反应的副产物之一盐酸的强酸性容易导致反应液的局部强酸性环境,而使反应产生的C18-GIu分子继续与L-谷氨酸反应,这大大增加了产物的后处理难度,很难得到高纯度的产物．因此,我们改用L-谷氨酸二乙酯为原料,在二环己基碳酰亚胺催化下或通过硬脂酰氯得到所需的高纯度产物．在此基础上,研究了．合成的C18-GIu及C18-GIu-2ES的成胶性质,结果表明C18-GIu-2ES具有比C18-GIu更广的成胶范围和更小的成胶浓度．     

酰肼衍生物的凝胶化行为

N,N-(5-烷氧基-1,3-苯二甲酰)-N',N'-二(4-甲基苯甲酰)二肼系列化合物(An)能在苯、甲苯、硝基苯及氯仿等有机溶液中形成有机凝胶. X射线衍射实验及扫描电子显微镜观察的结果显示, 在凝胶状态下, An分子聚集成层状有序排列, 并进一步堆积形成纤维网络结构. 红外光谱及核磁氢谱研究证实了分子间氢键码酰肼衍生物形成凝胶的驱动力. 另外, 侧链上烷基链的长度对凝胶的能力及凝胶的稳定性影响较大, 而对于凝胶的形貌及分子聚集的结构影响不大.     

含偶氮苯基元联酰胺衍生物的有机凝胶和光响应性质

设计合成了具有不同末端烷基链长度的偶氮苯类联酰胺衍生物N-(3,4-n-氧基苯基)-N'-4-(偶氮苯基)苯甲酰肼(Dn,n=7,8,10).Dn可以形成稳定的有机凝胶,末端烷基链增加有利于提高凝胶能力和热力学稳定性.凝胶形成的驱动力主要为联酰胺基团间的分子间氢键以及偶氮苯基团间的π-π相互作用和烷基链间的范德华力.在紫外光照射下,Dn中的反式偶氮苯向顺式转化,并且在溶液中的光响应性非常显著,但凝胶态下偶氮苯的光致顺反异构不能诱导凝胶-溶胶的转变.     

含偶氮苯基团的三枝状凝胶因子的合成和凝胶性质研究

设计合成了一种中心为三乙基氨基,酰胺基作为氢键连接基团,柔性的烷基链连接偶氮苯基团的含多种分子间弱相互作用的三枝状有机凝胶因子1.由于偶氮苯基团处于分子的外缘,在THF溶液中,凝胶因子1表现出良好的光致变色行为.凝胶性能测试中,分子间存在氢键作用、π-π相互作用等使得该化合物在醇类、有机酸类和乙腈等极性溶剂中极易形成稳定的有机凝胶.在少数的非极性溶剂,如正己烷和环己烷中也可以形成稳定凝胶,并且随着溶剂极性的不同,凝胶形貌呈现出规则的纤维状或带状结构.     

胆固醇分子印迹聚合有机凝胶的制备及其选择性吸附研究

以N-十八烷基马来酰胺酸(ODMA)为凝胶剂,在甲基丙烯酸β-羟乙酯、甲基丙烯酸、聚乙二醇二甲基丙烯酸酯和模板分子3-胆固醇酰氧基丙酸(COPA)混合物中自组装形成稳定的超分子有机凝胶,经UV原位光聚合,乙腈提取模板分子制备了胆固醇非共价印迹聚合有机凝胶.吸附实验在水/THF中进行.结果显示胆固醇非共价印迹聚合有机凝胶...     

不同功能基团的有机盐作为低相对分子质量凝胶因子对原油的成胶性能

低相对分子质量凝胶作为治理原油泄漏的材料具有一些优异的性能,但其在水油相中的成胶规律仍不明确,本文以有机酸及有机胺为原料设计合成了一系列有机盐。 通过核磁共振波谱仪(NMR)、傅里叶红外光谱仪(FTIR)、扫描电子显微镜(SEM)和倒挂实验等技术手段表征了有机盐的结构和成胶性能。 结果表明,有机盐A3C3(A3:肉桂酸;C3:月桂胺)在室温下能使原油形成稳定凝胶,成胶溶度为质量分数6%,该分子在溶剂中自组装形成树枝状三维网状结构。 凝胶的形成需要分子间π-π堆积作用、氢键、静电作用和范德华力等多种作用力协同作用,分子间的π-π堆积作用有利于凝胶的形成,含有多个苯环的凝胶因子更易在芳香族溶剂中形成凝胶。 这些成胶规律对处理原油泄漏的低相对分子质量凝胶因子的设计合成具有实际的指导意义。     

π-共轭三苯基苯衍生物的合成及其胶凝性能

合成了一系列三单脂肪链具有盘状结构的三苯基苯衍生物并研究了其在有机溶剂中自组装行为. 结果表明, 该系列衍生物在多种低极性有机溶剂中可以形成稳定的凝胶, 利用小角X射线衍射实验和扫描电子显微镜技术观察到干凝胶的分子排列具有层状结构, 形成纤维状和片层状聚集, 紫外-可见吸收光谱和红外光谱结果表明分子间氢键和π-π共轭堆积效应是形成自组装凝胶的主要驱动力. 在形成凝胶过程中, 凝胶剂分子在溶液中通过盘状中心的π-π共轭堆积效应和酰胺键的分子间氢键作用自组装成层状结构, 层状结构进一步组装形成纤维状和片层状聚集体, 最终形成三维网状结构阻碍溶剂流动形成凝胶.     

由凝胶因子形成的十四酸异丙酯超分子凝胶制备与表征

采用双十八烷基-L-苯丙氨酸(Bis18-L-Phe)为凝胶因子,制备了具有热可逆性的十四酸异丙酯(IPM)超分子凝胶。IPM凝胶相转变温度(Tgel)随Bis18-L-Phe浓度增大而增加。偏光显微镜(POM)显示在整个IPM凝胶中形成了相互缠绕的针状聚集体。FT-IR光谱分析表明Bis18-L-Phe分子间酰胺的氢键作用是IPM凝胶形成的一个重要驱动力。IPM凝胶动力学研究表明凝胶时间随Bis18-L-Phe浓度的增大而缩短,随着温度升高而延长,因此IPM凝胶时间可以通过温度和Bis18-L-Phe浓度调控。     

反应型凝胶剂2,4-二烷脲基甲苯衍生物及有机溶剂的室温凝胶化研究

通常制备有机分子凝胶是在高温下溶解凝胶剂,凝胶剂分子在冷却过程中进行自组装并使有机溶剂凝胶化.该方法限制了某些低沸点溶剂的凝胶化.利用甲苯二异氰酸酯与烷基胺的高反应活性,制备了3种反应型凝胶剂.这种反应型凝胶剂能以较低的浓度在室温下使某些芳香族和卤代烃溶剂形成热可逆的有机分子凝胶.场发射扫描电镜表明这种反应型凝胶剂在有机溶剂中自组装形成纤维状三维网络结构.随着烷基胺中的烷基链长度不同,形成的纤维状聚集体的形态也不同.FT-IR和1H NMR研究表明分子间氢键作用是反应型凝胶剂自组装的驱动力.通过XRD和分子模拟推测了其聚集体的结构形态.     

谷氨酸低分子量有机凝胶的药物控制释放行为

低分子量的有机胶凝剂组装形成的有机凝胶可应用于药物缓释体系.本研究中,使用亲水的钙黄绿素和疏水的布洛芬为模型分子,研究其在谷氨酸衍生物有机凝胶体系中的缓释行为.研究表明,与药物分子与有机胶凝剂简单混合的体系相比,亲水或疏水的药物分子在有机凝胶体系中的释放速度显著减缓.SEM的研究发现药物粒子嵌入在有机凝胶的三维网络中,因此,有机凝胶的三维网络结构可认为是实现药物缓慢释放的基质,药物分子从网络中的释放受限导致了其从有机凝胶中的缓释行为.     

天然五环三萜有机功能分子

天然五环三萜在自然界中广泛存在,由六个异戊二烯单元组成,可以从动植物中分离获取。因具有手性刚性骨架、多反应位点、独特组装性能、良好生物相容性及药理活性,其在超分子化学、智能材料、界面化学、药物传输等领域有着不可忽视的潜力。本文基于课题组近年来在天然五环三萜有机功能分子方面的工作,概述了含甘草次酸和甘草酸骨架的功能小分子和高分子的设计、合成及其在水凝胶、有机凝胶、有机-无机复合凝胶、手性材料、温敏和自愈合材料、农用Pickering乳液、准聚轮烷等方面的应用。     

Organogels from a vitamin C-based surfactant

A new double chained surfactant, 2-octyl-dodecanoyl-6-O-ascorbic acid (8ASC10), with a L-ascorbic acid unit as the polar headgroup was synthesized for the first time. The behavior of the compound in the dry solid state has been characterized through DSC, XRD, and SAXS measurements. The surfactant forms stable viscous organogels in the presence of suitable organic solvents and also water-induced organogels upon addition of water to the organogel. These mixtures show shear-thinning properties and are birefringent. The behavior and properties of the organogels have been studied through rheology, DSC, and SAXS experiments. The organogels possess the same antioxidant properties of the original L-ascorbic acid ring and can be used to solubilize and protect valuable organic molecules.     

胆固醇分子印迹的聚合有机凝胶及其吸附性能研究

报道了一种新型胆固醇分子印迹的聚合有机凝胶.以3-胆固醇酰氧基丙酸(COPA)为模板分子,通过可聚合凝胶剂N-十八烷基马来酰胺酸(ODMA)在甲基丙烯酸β-羟乙酯、甲基丙烯酸和聚乙二醇二甲基丙烯酸酯混合溶液的自组装,首先形成稳定的超分子有机凝胶,经UV光引发原位聚合,再经乙醇提取模板分子后制得胆固醇非共价印迹的聚合有机凝胶.偏光显微镜(POM)和场发射扫描电镜(FE-SEM)表明ODMA在单体混合物中自组装形成带状聚集体,这为其后形成的印迹聚合有机凝胶的孔穴稳定性提供了保证.印迹聚合有机凝胶对胆固醇的吸附效率可达到64%,并与ODMA和COPA的含量有关.实验表明,当ODMA的含量由1wt%增加到3 wt%时,吸附量由15.7 mg/g增加到22.9 mg/g.当COPA的含量由4 wt%增加到7 wt%时,吸附量由16.8 mg/g增加到22.2 mg/g.然而,当ODMA含量过多时,吸附量反而下降,这主要归因于体系网络密度的增加导致扩散阻力增加.而COPA含量过多时,可能干扰ODMA的自组装,影响印迹孔穴的稳定性,同样使得吸附量下降.     

Selective adsorption of D- and L-phenylalanine on molecularly-imprinted polymerized organogels formed using polymerizable gelator N-octadecyl maleamic acid

The polymerizable gelator N-octadecyl maleamic acid (ODMA) can self-assemble in selected polymerizable organic solvents, such as 2-hydroxyethyl methacrylate (HEMA) and methylacrylic acid (MAA) to form thermally stable polymerizable organogels. A mixture consisting of HEMA and MAA as the monomer and functional monomer, PEG dimethacrylates (PEG200DMA) as the crosslinker, BOC-L-phenylalanine (BPA) or L-phenylalanine ethyl ester (PEE) as the chiral templates, was gelatinized by ODMA firstly and subsequently polymerized by in situ UV irradiation or thermal initiation. The molecularly imprinted polymerized organogels were obtained after the removal of the templates through ethanol extraction. Selective adsorption of D- and L-phenylalanine was performed on the polymerized organogels. The results indicate rather high adsorption efficiency obtained for L-phenylalanine compared with that for D-phenylalanine, which was found to be dependent on the concentrations of ODMA, content of template, and the method of polymerization. Herein, the concentration of ODMA in the organogels played an important role for the adsorption efficiency of D- and L-phenylalanine.     

Architecture of a biocompatible supramolecular material by supersaturation-driven fabrication of its fiber network

The architecture of a biocompatible organogel formed by gelation of a small molecule organic gelator, N-lauroyl-L-glutamic acid di-n-butylamide, in isostearyl alcohol was investigated based on a supersaturation-driven crystallographic mismatch branching mechanism. By controlling the supersaturation of the system, the correlation length that determines the mesh size of the fiber network was finely tuned and the rheological properties of the gel were engineered. This approach is of considerable significance for many gel-based applications, such as controlled release of drugs that requires precise control of the mesh size. A direct cryo-transmission electron microscopy (TEM) imaging technique capable of preserving the network structure was used to visualize its nanostructure.     

客体小分子在超分子有机凝胶体系中的扩散释放

采用二(4-硬脂酰胺基苯基)甲烷(BSAPM)为凝胶剂制备了含有小分子水杨酸和若丹明B的1,1,2-三氯乙烷(TCE)超分子有机凝胶. 以超分子有机凝胶作为主体, 客体小分子水杨酸和若丹明B可轻微降低超分子有机凝胶的相转变温度(T_GS). 用紫外-可见光度法研究了超分子凝胶中两种客体小分子在静态下的扩散释放. 结果表明其释放率随凝胶剂浓度的增加而降低. 客体小分子的体积大小对其释放有明显的影响, 分子体积较大的若丹明B的释放率低于分子体积较小的水杨酸. 另外, 若丹明B的扩散系数也低于水杨酸, 且随凝胶剂浓度的增加, 这种趋势更为明显. 两种客体分子的累积释放率与时间的平方根成良好的线性关系, 符合Higuchi方程, 属扩散控制的Fickian释放机理.     

Gelation of organic solvents by N-(n-tetradecylcarbamoyl)-l-amino acids

A series of N-(n-alkylcarbamoyl)-l-amino acid amphiphiles with different amino acid head groups were designed and synthesised. The gelation abilities of these amphiphilic molecules were studied in toluene and p-xylene solvents. The hypothesis that steric crowding at the chiral head group destroys gelation ability of the amphiphile was examined. Indeed, beside l-alanine-based amphiphile, only l-serine and l-aspartic acid derivatives were found to gelate the organic liquids efficiently in the presence of a small quantity of water. The gels were characterised by a number of methods, including FT-IR, NMR and X-ray diffraction spectroscopy, scanning electron microscopy (SEM) and rheology. The SEM micrographs revealed three-dimensional networks of ribbon-like aggregates. The organogels were observed to be thermo-reversible in nature and have sufficient mechanical strength. The gels have gel-to-sol transition temperatures above the physiological temperature (310 K).     

Water-induced physical gelation of organic solvents by N-(n-alkylcarbamoyl)-L-alanine amphiphiles

A series of amino acid-based gelators N-(n-alkylcarbamoyl)-L-alanine were synthesized, and their gelation abilities in a series of organic solvents were tested. No gelation was observed in pure solvents employed. All the amphiphilic molecules were found to form stable organogels in the solvents in the presence of a small amount of water, methanol, or urea. The volume of solvent gelled by a given amount of the gelator was observed to depend upon the volume of added water. The gelation behavior of the amphiphiles in a given solvent containing a known volume of water was compared. The effects of chirality and substitution on the acid group on the gelation ability were examined. Although the corresponding N-(n-tetradecylcarbamoyl)-DL-alanine was found to form only weak organogel in pure solvents, the achiral amphiphilic compound N-(n-tetradecylcarbamoyl)-β-alanine, however, did not form gel in the absence of water. The methyl ester of N-(n-tetradecylcarbamoyl)-L-alanine was also observed to form gels in the same solvents, but only in the presence of water. The organogels were characterized by several techniques, including (1)H NMR, Fourier transform IR, X-ray diffraction, and field emission scanning electron microscopy. The thermal and rheological properties of the organogels were studied. The mechanical strength of the organogel formed by N-(n-tetradecylcarbamoyl)-DL-alanine was observed to increase upon the addition of water. It was concluded that water-mediated intermolecular hydrogen-bonding interaction between amphiphiles caused formation of supramolecular self-assemblies.     

Super organogelator based on tetrathiafulvalene with four amide derivatives and its F4TCNQ charge-transfer complex

A new series of tetrathiafulvalene-based organogelators endowed with four hydrophobic chains incorporating amide groups was synthesised and characterised. The resulting transparent organogels were obtained with organic solvents such as cyclohexane, carbon tetrachloride and chlorobenzene. Additionally, the length of the alkyl chain influenced the gelation ability of organogels. Considering the results, we concluded that compounds were ‘super gelators’. Interestingly, the gelators reacted with 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane to form charge-transfer (CT) complexes and binary organogels. ¹HNMR and FT-IR revealed that cooperation of hydrogen bonding, π–π and CT interactions was the main driving force for formation of the native and CT gels. The scanning electron microscopy images of native xerogels revealed characteristic gelation morphologies of three-dimensional cross-linking networks, whereas the morphologies of CT complex xerogels showed amorphous rod-like aggregates. X-ray powder diffraction studies suggested that both gelator and CT complex maintained lamellar molecular packing mode in organogel phase.