【作者】 周湘竹；

【导师】 郝京诚；

【作者基本信息】 山东大学 ， 化学， 2012， 博士

【摘要】 表面活性剂体系形成的聚集体结构、形状、尺寸和性质与形成机理,以及随之发生的相转变和转变过程中热力学和动力学问题仍然是表面活性剂科学研究的热点。表面活性剂复配体系以其能够简单快捷地形成新的产品而得以广泛研究,由于表面活性剂之间是以非共价键的方式作用,这样即可以利用各自的性能和优势,又可以发挥各种物质的协同效应。表面活性剂复配体系在溶液中能够自发形成各种有序聚集体,如球状和蠕虫状胶束、囊泡、层状液晶等,阴/阳离子表面活性剂体系就是其中杰出的代表。阴/阳离子表面活性剂体系呈现出丰富的相行为,而这些相行为的变化因素主要是阴离子和阳离子表面活性剂的混合比例、表面活性剂总浓度和表面活性剂的自身性质,如链长、极性头基类型等。这些体系一个显著的性质是能够自发形成阴/阳离子表面活性剂囊泡,而这些自发形成的囊泡能够稳定存在相当长的一段时间,可以作为一种模型体系来研究,具有重要的理论研究价值。卵磷脂作为一种生物表面活性剂,是细胞的重要组成成分,它能够促进神经传导,提高大脑活力；促进脂肪代谢,防止出现脂肪肝；改善血液循环,预防心、脑血管疾病,具有极高的营养和医学价值。卵磷脂具有乳化、润湿、分散、改善粘度以及生物降解性等,在表面活性剂聚集体的构筑及调控等方面有不同于普通表面活性剂的特点,能形成一些独特的聚集结构。研究卵磷脂参与形成的阴/阳离子表面活性剂复配体系,可为近年来兴起的纳米材料、生物技术以及医药研究提供基础。论文以阴/阳离子表面活性剂复配体系为模型体系,研究了模拟体系在高盐溶液中的聚集结构和性质以及它们与卵磷脂混合构筑的无盐阴/阳离子表面活性剂复配体系。第一章中简要介绍了与本论文研究相关的基本知识、国内外近年的研究动态以及选题的内容和研究意义。在第二章中,我们研究了无机盐NaBr、NaCl和KBr分别在阳离子表面活性剂TTABr和阴离子表面活性剂SDS溶液中从298.15K到353.15K的溶解度。无机盐在表面活性剂溶液中的溶解度随温度的增加而增加,与其在水中的溶解度随温度变化趋势相同。NaBr、NaCl和KBr在低于临界胶束浓度(cmc)的表面活性剂溶液中的溶解度大于它们在高于cmc溶液中的溶解度。NaBr和KBr在阳离子表面活性剂溶液TTABr中的溶解度随温度增加而显著增加,但是NaBr和NaCl在阴离子表面活性剂溶液SDS中的溶解度随温度升高增加缓慢。在考察温度范围内,无机盐在SDS溶液中的溶解度远小于其在水中的溶解度。而对于TTABr溶液则不同,当温度低于312.5K时,KBr和NaBr在TTABr溶液中的溶解度远小于其在水中的溶解度；当温度高于340.15K时,KBr和NaBr在TTABr溶液中的溶解度略高于其在水中溶解度：当温度在312.15～340.15K之间时,KBr和NaBr在TTABr溶液中的溶解度与其在水中溶解度相当。这些数据和结论对于物理化学和工业应用中无机盐和表面活性剂的相互作用提供了新的理解和基本数据。在第三章中,NaBr诱导阴/阳离子表面活性剂复配形成的无盐和含盐体系聚集体形貌发生了变化,具体研究的体系是：i)优质的稀土金属萃取剂二(2-乙基已基磷酸酯(HDEHP)和十四烷基三甲基氢氧化铵(TTAOH)混合体系,ii)HDEHP的钠盐NaDEHP (HDEHP+NaOH→NaDEHP+H2O)与十四烷基三甲基溴化铵(TTABr).随着盐的加入,无盐体系由Lα/L1两相转变成由囊泡组成的Lα相,含盐体系也转变成La相,即两个体系中聚集体形貌都发生了变化,但转变后形成的微观结构是完全不同的。对于无盐体系HDEPH/TTAOH/H2O,盐的加入使得聚集体从紧密堆积导致的形变严重的囊泡转变成尺寸小、分散度低、自发曲率稳定的囊泡相：而含盐体系NaDEHP/TTABr/H2O随溶液中Na+的增加,单分散的多层囊泡相转变成严重变形、曲率较小、体积较大的囊泡。偏光显微镜观察、流变学测量、2H和31P核磁共振和低温透视电子显微镜(cryo-TEM)都证明了这些精细微观结构的演变,并从能量和临界堆积参数理论解释了这两个体系中囊泡结构转变。改变盐浓度控制聚集体结构类型的转变为表面活性剂聚集体的转变提供新的理解,并有望能够为开展稀土元素囊泡相中的萃取和控制释放做出理论贡献。在第四章和第五章中,研究了卵磷脂参与构筑无盐阴/阳离子表面活性剂复配体系和卵磷脂与无盐阴／阳离子表面活性剂复配体系的相互作用以及结构演变。在第四章中,考察了卵磷脂/TTAOH/水体系,通过改变混合比率r可以观察到丰富的相行为。Cryo-TEM能够直观地观察到聚集结构,流变学实验测量了这些聚集结构的流变学性质,并证明这些结构的存在,同时1H和31P核磁共振谱图提供了卵磷脂与TTAOH相互作用的重要信息。在已有的研究结果中,卵磷脂与离子表面活性剂相互作用的研究集中在含水量少的条件下。这些体系形成的结构主要是层状相和浓密的多层囊泡相(尺寸大于5μm)。而在本章研究的体系中观察到了棒状胶束和单层囊泡的存在。有趣的是我们发现卵磷脂可以结合一些单链表面活性剂TTAOH形成囊泡,因此这个体系为在特殊条件下(比如碱性)在脂质体内封装药物提供了可能性。在第五章中,研究了卵磷脂与无盐阴/阳离子表面活性剂体系十四烷基三甲基氢氧化铵/正十四酸/水(TTAOH/MA/H2O)的相互作用。随卵磷脂与TTAM混合比例和表面活性剂总浓度的变化,体系卵磷脂/TTAM/H2O形成的聚集体结构不同,分别是六角相H,层状相L,和两相层状相/H2O和六角相/层状相。卵磷脂和TTAM在水溶液中都容易形成层状相或囊泡相,卵磷脂在水含量较低且温度较高时形成反相六角相,而混合体系卵磷脂/TTAM/H2O在水含量较多时室温下即能够形成六角相,这与卵磷脂和TTAM在水中的相行为不同。通过小角X射线散射结果,计算出层状相的双分子层厚度,从而推出在层状相中卵磷脂和TTAM分子的排列；对于六角相,利用SAXS能得知晶格参数,并推导出柱状聚集体之间的距离及其疏水区域的半径。此研究丰富了含卵磷脂体系的溶致液晶相种类,在生物技术尤其是DNA转染方面有着潜在的应用。更多还原

【Abstract】 The study on the self-assembly, structural transition and properties of surfactants in aqueous solutions is the focus of colloid and interface science. In most cases, the mixed systems of surfactants usually have more excellent performance than the single surfactant solutions. The cationic and anionic surfactants mixture system, called catanionic systems, is a typical example, which has unique characteristics. The catanionic systems display a large diversity of phases. An outstanding property of theses systems is their ability to spontaneously form catanionic vesicles which can remain stable for years. The addition of salts can affect the properties of surfactant solution. Lecithin is the best known of all natural surfactants. It is widely distributed in living nature, being a basic structural component of the lipid matrix of biological membranes and membranous organelles. And it widely uses in food industries, cosmetics, pharmacology, and biotechnology as an effective dispersive and emulsifying agent. All this explains the keen interest of investigators from different fields of science in s lecithin. The research on interaction between lecithin and the catanionic surfactant systems can provide fundamental knowledge for the nano materials, biotechnology and pharmaceutical technology.In this thesis we investigated that the phase transition of surfactant aggregates in salt solution and the catanionic surfactant systems with lecithin. The outline and contents of this doctoral thesis are as follows:Chapter Ⅰ is a brief introduction of basic knowledge of the research background, in which surfactant science are reviewed, especially we conferred about the general features concerning the catanionic systems. The object and scientific significance of this thesis are also discussed at the end of this chapter.In Chapter Ⅱ, we determined the solubility of three commercially available inorganic salts, NaBr, NaCl, and KBr in cationic tetradecyltrimethylammonium bromide (TTABr) and anionic sodium dodecyl sulfate (SDS) solutions from298.15K to353.15K, respectively. The data show that the solubility of three salts in SDS and TTABr solution increase progressively with temperature increasing, which is similar to those in water. The solubility of NaBr, NaCl and KBr in surfactant aqueous solutions with concentration below the critical micelle concentration (cmc) of TTABr or SDS is higher than those with concentrations above TTABr or SDS cmc. The solubility of NaCl and NaBr in SDS are much lower than those in water and increase slowly along with the temperature increasing. For the case of KBr and NaBr in TTABr, it becomes more complicated. When temperature is below T=312.15K, the solubility of KBr and NaBr are much lower than those in water. But the solubility become higher when temperature is above T=340.15K. And the data are similar to those in water between312.15K and340.15K. The solubility of inorganic salts in surfactant aqueous solutions is very important parameter in scientific research and industry. The data and the results of inorganic salts in surfactant aqueous solutions should provide the basic data and make for understanding for inorganic and surfactant industries.In Chapter Ⅲ, the phase behavior induced by adding NaBr in two systems of cationic and anionic (catanionic) mixtures with same surfactant components but salt-free and saline in water, i.e.,(ⅰ) an excellent extractant of rare-earth metal ions, di-(2-ethylhexyl) phosphate (HDEHP, commercial name:P204), mixing with a cationic trimethyltetradecylammonium hydroxide (TTAOH) and (ⅱ) the sodium salt of HDEHP, NaDEHP (HDEHP+NaOH→NaDEHP+H2O), mixing with tetradecyltrimethylammonium bromide (TTABr), were studied. With adding NaBr, the salt-free system was transferred from an original two-phase Lα/L1to single Lα phase consisting of vesicles, the saline system from a two-phase Lα/L1to single Lα phase of vesicles, too. A very interesting finding is that the both finally single Lα phases of the two systems contain vesicles having different hyperfine structures which could be induced by much higher ionic strength because of the addition of NaBr. For the salt-free system, the densely deformed and packed vesicles are transferred to smooth and spherical ones with the addition of NaBr. However, for the saline system, the spherical vesicles with a high spontaneous curvature are changed to be largely, densely, and remarkably deformed ones. The hyperfine vesicle evolvement was demonstrated by polarization observations, rheology measurements, deuterium and phosphorus nuclear magnetic resonance spectra (2H and31P NMR), and cryogenic transmission electron microscopy (cryo-TEM) images. The theoretical considerations of vesicle evolvement in the two systems were discussed from energy and packing parameter. This control over aggregate shape with salt concentration may provide an understanding of transmutation of surfactant aggregates originating from different surfactant systems.In Chapter Ⅳ the phase behavior, structures, and properties of lecithin/tetradecyltrimethylammonium hydroxide (TTAOH)/water systems were investigated by cryo-TEM, polarization optical microscope,1H and31P NMR spectra, surface tension and rheological measurements. With the variation of mixing molar ratio and concentration of lecithin and TTAOH, the system exhibits the phase transition from micelles (L1phase) to vesicles (La Phase) through a phase separation region. The rod-like micelles, uni-and multilamellar vesicles were determined by means of cryo-TEM observations. The surface tension and rheological measurements were performed to follow the phase transition. The samples of L1phases behave as Newton fluids at a low concentration of lecithin. With increasing of the lecithin concentration, a shear-thinning L1phase at the shear rate80s-1was found. The samples of La phases show viscoelastic properties of typical vesicles. The interactions between lecithin and TTAOH were monitored by]H and31P NMR spectra. These results could contribute towards the understanding of the basic function of lecithin in biological membranes and membranous organelles.In Chapter V, the phase equilibria in mixtures of lecithin and the salt-free catanionic system TTAOH/MA (Myristic acid)/H2O were studied with particular emphasis on the behavior of the lamellar and hexagonal liquid crystal. The solvent corner of this system features an extensive lamellar and hexagonal phase and which we have characterized by means of polarization optical microscope, small-angle X-ray scattering and rheology. The findings from X-ray scattering determine the structural parameters of lamellar and hexagonal phase, which indicate the arrangement of surfactant molecules in lamellar and hexagonal phase.更多还原