| Vesicles made of amphiphiles are closed bilayers, surfactant congeries and most similar with cell membranes. Because of vesicles special structures, they are always applied in drug encapsulation and target release, nanoparticles, microreactors, polymer hollow microspheres synthesis and so on. The scientists take great interests in vesicles preparation and properties. There are two ways to prepare vesicles: One, using the exterior energy to surfactants systems, such as ultrasonic and extrusion; the other, spontaneous formation at proper conditions, this way has many advantages, such as having simple operation process, the prepared vesicles bearing stable properties and so on. Firstly reported by Kaler and Zasadzinski in 1989, that vesicles may form spontaneously from a mixture of cationic and anionic single-chained surfactants, and then researchers begin to focus on investments in the vesicles of spontaneous formation.So far, the vesicles of spontaneous formation have been prepared from aqueous mixtures of cationic/anionic surfactants, nonionic surfactant/ cosurfactant, zwitterionic/ anionic surfactants and cationic/ cationic surfactants. Lots of scientists use cationic/anionic surfactants solution without salt and ionic inducement of heavy metal method to form vesicle. People are more and more interested in spontaneous vesicles, and stabilities of the vesicles that rarely studied are very important. In view of above-mentioned situations, I fix objects of the study are single-tailed cationic/anionic surfactants system and Gemini cationic/single-tailed anionic surfactants system. Here, the stability of spontaneous vesicles were studied in detail, and make use of vesicle template method to prepare polymer hollow microspheres.1. Study on Stability of the Vesicles in Single-tailed Cationic/ Anionic Surfactants System.In the single-tailed cationic surfactant (DTAB) and anionic surfactant (SDBS) composite system, vesicles can form spontaneously, the experiment results were in accordance with vesicle formation mechanisms that are Israelachvili theory and Masaniko geometry model theory.We employ TEM and Potential Analyzer to study on spontaneous formation vesicles in the composite system with n DTAB : n SDBS=4:6 at 30℃. The results show that: mean diameters of the vesicles increase with surfactants total concentrations, and are steady in a certain time. The system which surfactants total concentration is 0.045mol/L has favorable stability of time even after 6 months. The vesicles still exist after ethanol solvent or nonionic surfactant TritonX-100 addition, and also have well thermal stability. After inorganic salt NaBr addition, we find the Zeta potential decreased and 4μm tubelike structure materials. This phenomenon is considered as follows: added salt could screen the vesicle superficial charge and compress electrical double- layers of the congeries, the repulsion between vesicles decreased and vesicles fused, then tubelike structure materials formed. These research results provided references with further exploiting application of the vesicles.2. Study on Stability of the Vesicles in Gemini Cationic/ Single-tailed Anionic Surfactants System.Gemini cationic surfactant 16-3-16 is synthesized by N, N-dimethylcetyl tertiary amine with 1, 3-dibromopropane in dry ethanol under reflux. The best reaction condition is obtained by orthogonal experiment method with three factors and three levels: best ratio of reactants is n(tertiary amine): n(1,3- dibromopropane)=2.2: 1, reaction time is 60h, the volume fraction of dry ethanol in reaction mixture is 45%.The concentration of Gemini 16-3-16 and SDBS is respectively 5×10-3 mol/L in their composite system. Blue Ruguang could be seen when the amount of anionic surfactant is more than the cationic ones. Because anionic and cationic surfactants don't have chromophore group, the blue Ruguang might cause by scattering of congeries and particles. Finally, we choose the object of research is CTOT. = 5×10-3mol/L,n16-3-16 : nSDBS=4:6. TEM results show that vesicles fuse in various congery shapes with time lost. The congery shapes have two layers, thread, tube and branch likes. Vesicles could transform to tube and branch like congeries after ethanol, salt addition or temperature growing. But congeries could be destroyed after nonionic surfactant addition.At the same time, we test the surface activity and rheology property of Gemini 16-3-16 and SDBS composite system, the results show that Gemini surfactants with special structures have better surface activity than relevant common surfactants and better synergy than common ones in the composite systems; the composite system has obvious and complicated rheology behavior, viscosity change depends on concentration and shear velocity values at 25℃.3. Polymer Hollow Microsphere Preparation via Vesicle TemplateThe monomers of different quality scores addition to DTAB/SDBS composite system, we find that mean diameter of the vesicles grows with monomer amounts increasing, but diameter increases abruptly when monomer amount addition is more than 40wt%. The gigantic vesicles don't exist steadily, meanwhile we can see the solution comes to phase separation. So we choose the object of monomer amount with 30wt%; The polymer hollow microspheres could exist steadily after polymerization, TEM results show that phase separation and congregation don't happen after 1 month; mean diameter of the vesicles don't change after dilution, which speculates polymerization takes place in two layers of vesicles, diameter could be steady because of polymer confine; 0.02M nonionic surfactant don't destroy the polymer hollow microspheres; AFM results further throw out the polymerization reaction takes place between two lays of the vesicles, and polymer hollow microspheres have been prepared.
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