AOT微乳体系中纳米银的可控合成及其紫外-可见光谱研究  

Controllable Synthesis and UV-Vis Spectral Analysis of Silver Nanoparticles in AOT Microemulsion

作　　者：张万忠[1,2] 乔学亮[2] 罗浪里[2] 陈建国[2] 

机构地区：[1]南方医科大学药学院,广东广州510515 [2]华中科技大学材料学院,材料成形与模具技术国家重点实验室,湖北武汉430074

出　　处：《光谱学与光谱分析》2009年第3期789-792,共4页Spectroscopy and Spectral Analysis

基　　金：教育部高校博士点基金项目(20050487011)资助

摘　　要：在以琥珀酸二异辛酯磺酸钠(AOT)为表面活性剂、环己烷为连续相形成的W/O型微乳体系中,用增溶于微乳液水核中的AgNO3为银源、水合肼为还原剂制备了纳米银溶胶,利用UV-Vis光谱分析了Ag-NO3的浓度、AOT的浓度、还原剂的种类和水与表面活性剂的物质的量比(W)等参数对形成粒子数量及平均粒径的影响,为纳米银粒子的可控合成和纳米银的UV-Vis光谱解析提供了新的依据。研究表明,适当增大AgNO3的浓度,有利于形成粒径较小的纳米银粒子;W值增大,形成粒子的平均粒径和粒子数量明显增加。和NaBH4相比,水合肼在反胶束中的溶解性能较好,有利于微乳液反胶束中Ag+的还原。增大AOT的浓度,在一定范围内胶束对反应物的增溶能力增强,胶束的半径也相应减小,有利于形成数量较多、平均粒径较小的纳米银粒子。Colloidal silver nanopartieles were synthesized in water-in-oil microemulsion using silver nitrate solubilized in the water core of a microemulsion as source of silver ions, hydrazine hydrate solubilized in the water core of another one as reducing agent, cyclohexane as the continuous phase, and sodium bis（2-ethylhexyl） sulfosuccinate （AOT） as the surfactant. The main factors affecting the formation of silver nanoparticles were systematically studied. Ultraviolet-visible （UV-Vis） spectra were used for analyzing the effects of reaction parameters, including the type of reducing agents, the molar ratio of water to surfactant and the concentration of AgNO3 and AOT and so on, on the formation of silver nanoparticles. Original results for the controllable synthesis of silver nanoparticles were obtained when the synthesis proceeded in AOT-cyclohexane-AgNO3 microemulsion. The UV- Vis spectra of silver sols formed in the microemulsion with various parameters were studied systematically. The results show that the amount and average size of the obtained nanoparticles obviously depend on the above parameters. When the concentration of AgNO3 is lower, smaller silver nanoparticles are easy to form by increasing the concentration of AgNO3 appropriately. The higher W value was found to form larger numbers of silver nanoparticles with larger particle size. Compared to the solubility of NaBH4 in AOT reverse micelles, hydrazine hydrate is well soluble in these micelles, and thus it is favorable to reduce the sil- ver ions solubilized in the water core of AOT-cyclohexane-AgNO3 microemulsion. The increase in the concentration of AOT induces an increase in the number of AOT mieelles and a decrease in the molar ratio of water to surfactant. As a result, the solubilization capacity of reactants in the micelles increases and the radii of the micelles decrease. That is to say, with the increase in AOT concentration, the amount of the formed nanoparticles increases and the average size of the particles decreases.

关 键 词：纳米银 AOT微乳液 可控合成 UV-VIS光谱 

分 类 号：O657.3[理学—分析化学]