α-羧基氧化胺表面活性剂的pH响应自组装行为研究

发布时间：2018-03-05 20:18

本文选题：刺激响应型表面活性剂　切入点：囊泡　出处：《江南大学》2017年硕士论文　论文类型：学位论文

【摘要】：环境刺激响应型表面活性剂可通过外界条件(如光、热、磁、电、pH、湿度、压力、电解质浓度等)的改变实现有序自组装聚集体结构切换的调控,在可控药物缓释、可控微流体器件和纳米微反应器等高新技术领域具有诱人的应用前景,与能源、信息和智能传感器等领域的新材料和新技术开发密切相关,已成为智能流体的重要研究方向之一。pH响应表面活性剂智能流体具有调控方便、响应迅速、成本低和响应可逆等显著特点。文献中主要通过表面活性剂复配、表面活性剂溶液中引入功能性添加剂和表面活性剂单一组分进行pH响应表面活性剂智能流体的构建。本文由天然脂肪酸合成了分子结构中同时含有氧化胺基团和羧酸基团的α-羧基十三烷基二甲基氧化胺(CTAO)和α-羧基十五烷基二甲基氧化胺(CPAO),成功获得了不需任何添加剂即可发生囊泡-蠕虫状胶束-球状胶束多重转变的pH响应智能流体单组分体系,在pH变化单位约为1的范围内即出现两次显著的流变性能突变;考察了温度和浓度对CTAO和CPAO形成的囊泡和蠕虫状胶束的影响,探讨了CTAO和CPAO自组装pH响应的作用机制;基于pH灵敏响应的智能流体,探索引入商品化的光致生酸剂,将其转化为光响应的智能流体。主要工作概括如下:由天然脂肪酸经氯代、胺解、氧化三步合成表面活性剂CTAO和CPAO,用FT-IR和1H NMR等技术对表面活性剂的结构进行分析表征。利用酸碱滴定法、电导率仪、Zeta电位分析仪确定CTAO和CPAO的pKa1、pKa2值和等电点,并确定其在溶液中的分子存在形式。运用流变仪对不同pH值下CTAO/CPAO的流变行为进行考察,通过低温透射电镜(cyro-TEM)和扫描电子显微镜(SEM)对不同pH时CTAO和CPAO自组装聚集体的微观结构进行了表征。实验发现在无需任何添加剂的条件下,所研究表面活性剂水溶液具有灵敏的pH响应特征:当pH较低时,CTAO(pH 2.0~5.6)和CPAO(pH 2.3~5.8)自组装形成囊泡结构;当继续升高pH时,CTAO(pH 6.0~6.7)和CPAO(pH 6.2~7.4)形成具有线性粘弹性流体行为特征的蠕虫状胶束,在很窄的pH范围内零剪切粘度变化可达三个数量级;当pH高于中性时,CTAO(pH7)和CPAO(pH8)溶液中表面活性剂以球状胶束形式存在。考察了温度和浓度等对CTAO和CPAO囊泡体系和蠕虫状胶束结构的影响。通过测定不同pH条件下CTAO和CPAO溶液的表面张力,考察两种氧化胺表面活性剂单个分子占据面积随溶液pH变化的变化规律。实验结果表明,随着pH的增大,两种表面活性剂表面张力和临界胶束浓度均逐渐增加,说明分子存在形式和分子间相互作用发生变化,引起分子堆积参数发生改变,从而导致溶液中发生聚集体形貌的转变。基于CTAO对pH灵敏的刺激响应性,探索将光致生酸剂引入pH响应体系,通过光照引发pH耦合变化,诱导自组装胶束结构的转变,得到了基于pH响应的光刺激响应智能流体。
[Abstract]:Environmental stimulation-responsive surfactants can be controlled by changing the external conditions (such as light, heat, magnetism, pH, humidity, pressure, electrolyte concentration, etc.). Controllable microfluidic devices and nanoscale microreactors have attractive application prospects, which are closely related to the development of new materials and technologies in the fields of energy, information and intelligent sensors. It has become one of the important research directions of intelligent fluid. Ph responsive surfactant intelligent fluid has many remarkable characteristics, such as convenient control, rapid response, low cost and reversible response. In this paper, functional additives and a single component of surfactant were introduced into surfactant solution to construct the intelligent surfactant fluid in pH response. In this paper, the molecular structure of surfactants containing amine oxide group and amine oxide group was synthesized from natural fatty acids. The 伪 -carboxyl 13 alkyl dimethyl amine oxide (CTAO) and 伪 -carboxyl 15 alkyl dimethyl amine oxide (CPAOO) of carboxylic acid group have been successfully obtained. The pH response of vesicle to vermicelle micelle to spherical micelle multifold transition can be obtained without any additive. Intelligent single component fluid system, Two significant rheological changes occurred in the pH range of about 1. The effects of temperature and concentration on the vesicles and worm-like micelles formed by CTAO and CPAO were investigated, and the mechanism of the pH response of CTAO and CPAO self-assembly was discussed. Based on the pH sensitive intelligent fluid, this paper explores the introduction of commercial photogenic acidogenic agent and converts it into a light responsive intelligent fluid. The main work is summarized as follows: chlorination and amination of natural fatty acids, Surface active agents CTAO and CPAOwere synthesized by oxidation and characterized by FT-IR and 1H NMR. The value and isoelectric point of CTAO and CPAO were determined by acid-base titration and Zeta potential analyzer. The rheological behavior of CTAO/CPAO at different pH values was investigated by rheometer. The microstructure of CTAO and CPAO self-assembled aggregates at different pH was characterized by low temperature transmission electron microscopy (TEM) and scanning electron microscope (SEM). The surfactant aqueous solution has the characteristics of sensitive pH response: CTAO (pH 2.0 ~ 5.6) and CPAO(pH 2.3 (5.8)) self-assemble vesicle structure when pH is low; CTAO (pH 6.0 ~ 6.7) and CPAO(pH 6.2n (7.4) form worm-like micelles with linear viscoelastic fluid behavior when pH continues to increase. The change of zero shear viscosity can reach three orders of magnitude in a narrow pH range. When pH was higher than neutral, the surfactants existed in the form of spherical micelles. The effects of temperature and concentration on the vesicles of CTAO and CPAO and the structure of wormlike micelles were investigated. CTAO and CPAO were determined under different pH conditions. The surface tension of the solution, The surface tension and critical micelle concentration of the two surfactants were increased with the increase of pH, the results showed that the surface tension and the critical micelle concentration of the two surfactants increased gradually with the increase of pH, and the surface tension and the critical micelle concentration of the two surfactants increased gradually with the increase of pH. The results show that the existing forms of molecules and the intermolecular interactions change, which leads to the change of molecular accumulation parameters, which leads to the transformation of the morphology of aggregates in solution. Based on the sensitivity of CTAO to pH stimulation, The photoinduced acidogenic agent was introduced into the pH response system, and the light induced pH coupling was used to induce the transformation of the self-assembled micelle structure. The photostimulation-responsive intelligent fluid based on the pH response was obtained.
【学位授予单位】：江南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O647.2

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