表面活性剂溶液聚集转变过程中的热力学研究

发布时间：2018-05-03 11:02

本文选题：季铵盐阳离子表面活性剂 + 临界胶束浓度　；参考：《聊城大学》2017年硕士论文

【摘要】：表面活性剂在日常生活与生产中普遍存在,广泛应用于医药、石油、日用洗化等领域。因此人们对于两亲性表面活性剂分子的可控自组装的关注日趋密切。本论文拟应用阴、阳离子型表面活性剂分别与不同添加剂形成稳定的混合体系,利用分子间的相互作用设计构筑可温度调控的胶束体系。主要通过电导、流变以及量热等测量技术,测定胶束溶液中分子聚集状态的转变,并得到相关的动力学和热力学参数。结合核磁、电镜、小角X散射等技术,系统考察温度调控下表面活性剂分子在水溶液中聚集状态的转变机制和规律,从分子水平揭示转变过程中分子间的相互作用机理。这对加深表面活性剂分子自组装领域中有关规律的理解具有非常重要的意义。本论文作为国家自然科学基金资助项目(No.21473084和No.21073081)的部分工作,具体工作如下:(一)单链季铵盐阳离子表面活性剂纯溶液体系中胶束转变过程的热力学研究探讨了季铵盐阳离子表面活性剂(CnTAB、CnHTAB,n=12,14,16)的纯溶液体系中的聚集状态转变。采用电导法测定了以上两系列表面活性剂在不同温度下的第一和第二临界胶束浓度(CMC1,CMC2),并应用等温滴定微量热法测量了聚集体转变过程中的热量变化,得到了一系列的热力学参数。最后利用核磁共振谱图法得到的质子H的化学位移,对不同浓度的水溶液中表面活性剂的头基所处的微环境与头基之间相互作用进行了分析。(二)阴离子表面活性剂与离子液体形成的双水相体系的热力学研究探讨了阴离子表面活性剂(十二烷基苯磺酸钠,SDBS)和咪唑离子液体1-丁基-3-甲基咪唑四氟硼酸盐([B4mim]BF4)形成的水溶液两相体系:上相是富表面活性剂相,下相为富离子液体相。利用目测法,绘制了1-丁基-3-甲基咪唑四氟硼酸盐([Bmim]BF4)、十二烷基苯磺酸钠(SDBS)和水组成的三元体系在298.15 K下的三元相图。在双水相区域周围选取几个不同组成的样品,利用等温滴定微量热法(ITC)测定了样品滴定过程中体系热量的变化。结果发现,随着样品中水含量的增加,量热曲线会表现出一个不太明显的吸热和放热过程,且与三元相图中双水相的形成和消失的位置完全吻合,这说明对于双水相体系的研究,ITC是一种可行且有效的方法。(三)双链季铵盐阳离子表面活性剂与非离子型表面活性剂形成的胶束体系的相行为和温度响应特性的研究对阳离子型双子表面活性剂2-羟亚丙基-1,3-双(二甲基十四烷基氯化铵)(14-3(OH)-14(2Cl)),非离子型表面活性剂聚氧乙烯月桂醚(C12H25(OCH2CH2)10OH,Brij-30)和水组成的三元体系的相行为进行了研究,并绘制出精确的相图。在相图确定的几个不同的相位区域中,我们对具有温度响应性的黏弹性蠕虫状胶束溶液区域进行了研究。研究的重点是随着温度和Brij-30含量的增加溶液黏弹性的变化。我们利用流变学分析对不同溶液中的结构变化以及影响胶束生长的各种因素进行了调查。并通过多种技术来研究系统中发生的相变过程,这些技术包括低温透射电镜,小角X射线散射和差示扫描量热。在所得到的结果的基础上,对聚集体的转化机理进行了分析。
[Abstract]:Surfactants are widely used in daily life and production and are widely used in the fields of medicine, oil and daily use. Therefore, people pay more attention to the controlled self-assembly of the two proactive surfactant molecules. A thermo controlled micellar system was designed by intermolecular interaction. The transformation of molecular aggregation state in micellar solution was determined mainly through measurement techniques such as conductivity, rheology and calorimetry. The related kinetic and thermodynamic parameters were obtained. The surface activity under the temperature regulation was systematically investigated by the technology of nuclear magnetic, electron microscopy and small angle X scattering. The mechanism and regularity of the aggregation state of the molecules in aqueous solution and the mechanism of intermolecular interaction in the transition process are revealed from the molecular level. This is very important for understanding the relevant rules in the field of molecular self-assembly of surfactants. This paper is a funded project of National Natural Science Fund (No.21473084 and No). .21073081) part of the work, the specific work is as follows: (1) the thermodynamic study of the micellar transformation process in the pure solution system of single chain quaternary ammonium salt cationic surfactant. The transition of the aggregation state in the pure solution system of quaternary ammonium cationic surfactant (CnTAB, CnHTAB, n=12,14,16) was investigated. The above two series of surfaces were measured by conductivity method. The first and second critical micelle concentrations (CMC1, CMC2) of the active agent at different temperatures were measured by isothermal titration microcalorimetry, and a series of thermodynamic parameters were obtained. Finally, the chemical shift of proton H obtained by NMR spectroscopy was used for the surface activity of different concentrations of aqueous solutions. The interaction between the microenvironment and the head base was analyzed. (two) the thermodynamic study of the biaqueous phase system formed by the anionic surfactant and the ionic liquid discussed the anionic surfactants (twelve alkylbenzene sulfonates, SDBS) and the imidazole ionic liquid 1- butyl -3- methyl imidazole tetrafluorborate ([B4mim]BF4) The two phase system of water solution is formed: the upper phase is the rich surface active agent phase and the lower phase is the rich ionic liquid phase. By using the visual method, the phase diagram of the three element system of 1- butyl -3- methyl imidazole tetrafluoroborate ([Bmim]BF4), twelve alkyl benzene sulfonate (SDBS) and water is drawn under 298.15 K. Several different groups are selected around the water phase region. The changes in the system heat in the sample titration were measured by the isothermal titration microcalorimetry (ITC). The results showed that with the increase of water content in the sample, the heat absorption and exothermic process showed a less obvious heat absorption and exothermic process, which coincided with the position of the formation and disappearance of the water phase in the phase diagram of the three element. The study of the aqueous two-phase system, ITC is a feasible and effective method. (three) the phase behavior and temperature response characteristics of the micellar system formed by the double chain quaternary ammonium salt cationic surfactant and the nonionic surfactants are studied on the cationic gemini surfactant 2- hydroxypropyl -1,3- double (two methyl fourteen alkyl ammonium chloride) (14-3 (OH) -) - 14 (2Cl)) the phase behavior of the non ionic surfactant polyoxyethylene lauryl ether (C12H25 (OCH2CH2) 10OH, Brij-30) and the three element system composed of water was studied and the exact phase diagram was drawn. In several different phase regions determined by the phase diagram, we have studied the area of the viscoelastic vermicular micelle solution with the temperature response. The focus of the study is on the changes in the viscoelasticity of the solution with the increase of temperature and Brij-30 content. We use rheological analysis to investigate the structural changes in different solutions and the various factors affecting the growth of micelles. And a variety of techniques are used to study the phase transition process in the system, including low temperature transmission electron microscopy, Small angle X ray scattering and differential scanning calorimetry. Based on the obtained results, the transformation mechanism of aggregates was analyzed.

【学位授予单位】：聊城大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O647.2

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