【作者】 孟君；

【导师】 路遥；

【作者基本信息】 中国科学院研究生院（理化技术研究所） ， 应用化学， 2009， 硕士

【摘要】 表面活性剂分子具有既亲水又亲油的“双亲”特性,目前已被广泛地应用各个领域,成为工业生产和日常生活中不可或缺的一种助剂。近年来,新一代表面活性剂Gemini,正逐渐成为相关领域的研究热点。它改变了传统表面活性剂的结构,具有更优良的性能。对它的研究从开始的结构设计、合成和分析,逐步扩展到界面行为、聚集体性质、协同效应及应用等方面。因此继续开发新的方法来更好的研究各种表面活性剂性能、作用规律和原理具有非常重要的意义。本论文在前人工作基础上,主要应用超微电极研究了CTAB水溶液胶束性质并且首次探索了其在Gemini表面活性剂水溶液性质研究中的应用。通过用超微电极测量胶束扩散系数变化,重点研究了添加剂对表面活性剂水溶液性质的影响,涉及到界面张力和胶束形状、大小、扩散、相互作用等多方面的内容,讨论了相关的规律和机理,加深了对胶束的微观结构变化和一些重要性质的理解。主要研究内容及其结果如下:1.用超微电极循环伏安法测量CTAB胶束的扩散系数,用时间分辨荧光法得到CTAB的胶束聚集数,根据这两种方法得到的实验结果,计算其他的胶束参数如有效半径(a)、胶束的表面积(S)、单个CTAB分子所占的面积(A)和排列参数(P),研究邻苯二酚对CTAB水溶液中胶束大小和形状的影响。结果表明:邻苯二酚的加入能够加速胶束变大,促进胶束形状变化,即由球形转变为棒状。2.用旋滴法测定烷基苯磺酸盐Gemini表面活性剂Ia水溶液与烷烃的界面张力,用超微电极循环伏安法测量Ia水溶液中胶束的扩散系数,研究NaCl对Ia水溶液性质的影响。结果发现:NaCl的加入能够使Ia胶束的扩散系数变大,界面张力降低,这些变化是因为NaCl的加入增强了静电屏蔽作用,降低了Ia离子头基之间的静电斥力,使得Ia分子排列更加紧密,从而使胶束形状变小,更有效的降低油水的界面张力,同时胶束表面电荷得到中和,胶束的静电斥力相应减小,胶束流动性相应的增加,表现出较大的胶束扩散系数。更多还原

【Abstract】 Surfactants are widely used in various fields and becoming necessary additive in industrial production and people’s daily life due to their unique properties. In recent years, the new generation of surfactant, Gemini surfactant, is becoming the researching hotspot of relative fields. The Gemini surfactant improves the structure of traditional surfactant and performs better property than the traditional surfactant. The research ranges from its structure design, composition and analysis to interface activity, quality of the congeries, cooperating effect and application, etc. Therefore, it’s importance to develop new researching methods to study the performance, functioning rule and principle of the surfactants.Based on the existing researches, this work enlarges the application of the ultamicroelectrode voltammetry in the surfactant system, mainly its application in research of the quality of traditional surfactants and Gemini surfactant. The ultamicroelectrode voltammetry is used to measure the diffusion coefficient change of micelle, the effect of the additives on the quality of the surfactant solution is specially studied. The study includes interface tension, micelle shape, size, diffuse and interaction, relative rules and mechanism are discussed, and a deeper comprehension of the microcosmic structure change of the congeries and some important property is realized.The main contents and the results are as follows:1. The effects of catechol on the change of cetyltrimethylammonium bromide (CTAB) micelles in aqueous solutions have been studied by Ultramicroelectrode (UME) cyclic voltammetry and Time-Resolved Fluorescence Quenching (TRFQ). It has been shown that the diffusion coefficient decreases and the micelle aggregation number increases with the addition of catechol. In order to analyze the change of the micelles, other micelle parameters like the effective radius (a), surface area of micelle (S), area of single CTAB molecule (A) and packing parameter (P) were calculated. All the results show that catechol can accelerate the increase of the aggregate size and sphere-to-rod morphology change of CTAB micelles even with lower concentration of CTAB.2. The effects of NaCl on the properties of alkylbenzene sulfonate Gemini surfactant have been investigated by spinning drop method and Ultramicroelectrode (UME) cyclic voltammetry. Spinning drop method and UME are used to measure the interfacial tension between Gemini Ia aqueous solution and heptane, the diffusion coefficient of Ia in aqueous solutions. It has been shown that the interfacial tension decreases and the diffusion coefficient increases with the addition of Nacl. This is because that electrostatic force reduces the electrostatic repulsion forces between ionic groups of Ia, which leads to a tighter arrangement of Ia and then reduces the interfacial tension and diminishes the size of micelles; micelles surface charge has been neutralized, so the electrostatic repulsion force between micelles decreases and the mobility of the micelles increases, which shows a larger diffusion coefficient.更多还原