【作者】 王雪辉；

【导师】 陈启明；

【作者基本信息】 华东师范大学 ， 物理化学， 2010， 硕士

【摘要】 胶体晶体(colloid crystal)指由亚微米级(meso-)或纳米级(nano-)的单分散胶体微球经过特定的排列方式构成的二维或三维有序的、类似于晶体结构的体系。由于其结构特性,在很多领域都有广泛的应用。单分散二氧化硅因尺寸分布狭窄,可以通过自组装法制备胶体晶体,应用于涂料、医药等方面。超微氧化镍粉作为一种纳米金属材料,在很多领域都有广泛的应用,可以作为催化剂、电池材料、硬质合金粘结剂等。核壳结构材料因其组成、大小、结构不同可以得到一些多功能的材料。通过在二氧化硅表面包覆氢氧化镍可以降低催化剂的成本,同时也可以增加催化剂的红外吸收,拓宽催化剂的使用范围和实用价值。而在氢氧化镍表面包覆二氧化硅则可以大大改善材料的韧性、耐磨性和耐腐蚀性。本文在大量文献调研的基础上,主要做了以下几个方面的工作。1.用不同纯度的TEOS制备单分散的二氧化硅颗粒,用透射电镜,动态光散射进行表征,研究原料纯度对产品单分散性影响,在此基础上进一步完善二氧化硅的成核机理,并以此指导制备单分散的二氧化硅；通过垂直沉降法对合成的二氧化硅进行组装,通过扫描电镜表征组装效果,并对组装缺陷进行分析。2.以TritonX-100,正庚烷,正己醇为体系,用微乳液法制备了单分散的氢氧化镍,讨论了不同条件对纳米颗粒的尺寸的影响：(1)微乳液的组成对颗粒尺寸有影响,但是不是主要因素；(2)随着氢氧化钠浓度的增加,颗粒的尺寸逐渐减小(3)在硫酸镍浓度小于0.05mol·L-1时,颗粒尺寸不受硫酸镍浓度的影响,超过此浓度时随着浓度的增大颗粒尺寸增大。结果表明：颗粒的形成和生长不仅与微乳液组成、氢氧化钠浓度、硫酸镍浓度组成有关,还与反应速率有关。3.分别采用配位沉淀法制备了两种核壳结构,通过透射电镜(TEM),X-射线衍射(XRD)表征表明：用该法在二氧化硅表面包覆氢氧化镍得到的纳米材料包覆均匀,没有出现未被包覆的二氧化硅颗粒；在氢氧化镍表面包覆二氧化硅时包覆效果较好,但是颗粒的单分散性不好,所以该反应条件有待于进一步探索。更多还原

【Abstract】 Colloidal crystals are one of the systems constituted of meso or nano monodispersed colloidal which is ordered through a particular arrangement of the two or three dimensional. For the structural characteristics, it is used in many different areas. Monodispersed silica after self-assembled, with narrow size distribution,can be applied in paint, medicine and so on.Ultrafine nickel oxide powder, a nano-metallic material, has been used in many areas, such as catalysts, battery materials, adhesives and other hard alloy. Core-shell structural materials because of its composition, size, and different structures can be made into multi-functional materials. The cost of crystal can be reduced by coating nickel hydroxide onto silica. Also, the infrared absorption of the catalyst would be increased and the field of application. The coating of silica on nickel hydroxide can improve the toughness, wear resistance and corrosion resistance. Based on the plenty of the present literature, we mainly have carried out the following work.1. The monodispersed silicon dioxide colloidal particles were synthesized with TEOS of different purity.TEM, DLS were used to judge the size distribution of silicon dioxide and then explore the influence of the purity of raw materials on the particle size. It can be used to further the mechanism of silica nucleation and guide preparation on monodispersed silica. The silica then was assembled by the vertical deposition method. We can judge the quality of the colloidal crystal by observing the scanning electron microscope, after which we analyze the lacuna.2. The monodispersed nickel was prepared with micro-emulsion in solution of Triton X-100,n-heptane,n-hexyl alcohol. The effect of different conditions on the size of nano-particles:(1) The composition of micro emulsion affect the particle size, however, was not the main factor;(2) The size of particles gradually decreased with the increase of NaOH concentration;(3) The particle size keep unaltered while the concentration of the nickel sulfate is less than 0.05mol·L-1; The particle size increases with the concentration of the nickel sulfate. It showed that:the factors which influence the particle size included not only the concentration of sodium hydroxide and nickel sulfate but also the reaction rate of the reaction itself.3. Coordination precipitation was used to prepare two kinds of core-shell structure. Through TEM and XRD, we know that the silica coated on the nickel hydroxide was symmetrical and dissociative silica didn’t appear; the effect of nickel hydroxide coated on silica was good, but with bad distribution. So the condition of reaction should be further explored.更多还原