The Establishment Of Quarternary Microemulsion And Its Application For Synthesis Of Nanomaterials

Recently, reverse phase emulsion system has been widely applied to nanomaterial design and fabrication. The nanoparticle synthesized by emulsion method has some advantages than traditional methods, for example, the nanoparticle has maller size, more uniform distribution and is less-likely to aggregate. LDHs belong to two dimensions nano-material which has unique layered structure. The layer is positively charged and the composition is able to be controlled, besides, the balancing anion in the layer can be easy to replace. Thus, LDHs possess different functions which have showed a good prospect in application in the fields of biomedicine and catalyst. However, the single structure has greatly restricted application of LDHs, and therefore it is significant to prepare hierarchical nano-LDHs to further enrich the fabrication and application of LDHs. There are three reseach parts in this paper:The established reverse phase emulsion system. The traditional titration was adopted to obtain the phase change point by sight. The ternary phase diagram was drawn to determine composition of stable system. Cationic surfactant CTAB as surfactant, the different influence factor on the reverse phase emulsion system such as solution pH value, different kinds of cosurfactant, the scale of CTAB to n-hexanol and solution concentration was investigated. The experiment results showed that when n-hexanol selected as cosurfactant and mass scale of CTAB to n-hexanol was 5:5, the system had the largest stable area, and the temperature, the solution pH value had little effect on the stable area of the reverse phase emulsion system, and the stable area of the system decreased sharply when the salt concentration increased from 0 mol·L-1 to 0.45 mol·L-1. The appropriate reaction condition was determined as the reaction being 30?, pH=10, and the solution concentration being 0.3mol·L-1.The above-mentioned reverse phase emulsion system was utilized to synthesize LDHs. The external factors like co value, crystallization time, ammonium hydroxide concentration and the species of salt concentration impact on the LDHs were investigated, the governable synthesis of Mg-Al-LDHs was determined. The experiment results showed that size of the product was controlled below 50 nm by increasing aging time, reducing the concentration of ammonia hydroxide and changing the value of ?, laying the foundation for LDHs for biosystem. Besides kinds of LDHs, ZnS nanodots were synthesized in the same way. The results indicate that emulsion system is applicable not only to kinds of LDHs but also to nanodots synthesis.Spherical and flower-like hierarchical LDHs were synthesized by above-mentioned reverse phase emulsion system. The effects of pH value and ? value on the morphology of hierarchical LDHs were investigated. Spherical and flower-like LDHs were successfully prepared in the above-mentioned reverse phase emulsion system. The structure and shape of all products were characterized and mechanisms for the forming of flower-like hierarchical LDHs were discussed. By changing the value of ?can control the morphology of Mg-Al-LDHs, and the results indicate that surfactant playing a special guiding role in the process of formation affects the nucleation and growth of crystals, and lead to directional arrangement of nano-materials. When the concentration of ammonia hydroxide increased from 1 mol·L-1 to 3 mol·L-1, supersaturation is increase leading to surface content descrease, and the flower-like structure were smaller and even vanished.In conclusion, this paper established the quaternary reverse phase emulsion system, and reported controllable synthesis of LDHs and ZnS by established microemulsion system and the preparation of nano-flower LDHs. This paper shows great value for the preparation and application of LDHs.