Preparating of Ultrafine Particles in Inorgaic Gel and Their Fixation

大多数功能材料是由纳米颗粒组成的，只有纳米颗粒分散良好，功能材料才具有优越的功能。然而，由于颗粒具有强烈的凝聚倾向，人们在寻找纳米颗粒的分散方法和分散状态的固定方法方面做了很多努力。本课题将胶体金作为纳米粒子，应用于催化剂、非线性光学器件和表面拉曼增强分析物质等功能材料。研究了金纳米粒子的分散和固定方法，得到以下结论：1)利用材料的胶凝现象作为固定方法。固定材料主要为合成粘土（拉土XLG）。金纳米颗粒也在粘土悬浮液中形成，并固定在粘土凝胶中保持分散状态。通过干燥法制备了金层配合物干膜，其结构可通过干燥法控制。2)采用表面带负电荷的二氧化硅溶胶和表面带正电荷的氧化铝、二氧化钛溶胶考察了固定材料表面变化对金纳米粒子分散状态的影响，二氧化硅浓度不能控制胶体金的状态。另一方面，带正电荷的金离子吸附在溶胶表面。固相浓度较低时，纳米颗粒常呈三角形或六角形，并很快凝固。随着固定液浓度的增加，分散状态得到改善。4)以PAANa聚合物的Laponite XLG粘土为固定材料，制备出粒径可控的金纳米颗粒，并保持分散状态固定在材料中。3)在水溶性聚合物溶液中制备金纳米颗粒，并与粘土凝胶进行比较。金离子仅吸附在聚2-乙烯吡啶（P2VP）上，P2VP是一种阳离子聚电解质。而阴离子胶体金则吸附在P2VP和聚丙烯酸钠（PAANa）上，尽管PAANa是阴离子聚电解质。聚合物的浓度和平均分子量影响胶体金的粒径和形成速率。少

Most of functional materials consist of nanoparticles, which only have superior functions when nanoparticles disperse well. Due to the strong tendency of the coagulation of particles, however, there are many efforts to seek the dispersion methods of nanoparticles and the fixation methods of the dispersion state. In this projects, colloidal gold was used as nanoparticles, which could be applied to the functional materials, such as catalysis, non-linear optical device and substance for the surface Raman enhanced analysis. I investigated about the dispersion and fixation methods of gold nanoparticles, and then got following conclusion.1) The gelation phenomena of materials were used as the fixation method.The materials for fixation was mainly synthetic clay (Laponite XLG). Gold nanoparticles were also formed in the clay suspension, and fixed in the clay gel keeping the dispersion state. The dry membrane with gold-lay complex made by drying, and its structure could be controlled by the dry … More ing method.2) Effects of surface change of material for fixation on the dispersion state of gold nanoparticles were investigated by using silica (negative surface charge), and alumina and titania (positive surface charge) sol. The silica concentration could not control the state of colloidal gold. On the other hand, gold ion adsorbed on the surface of sol with positive charge. Nanoparticles were often observed to have triangle or hexagonal shape when the sol concentration for fixation was low, and then coagulated soon. The dispersion state was improved as the sol concentration for fixation increased.4) Gold nanoparticles can be prepared with the controlled particle size and fixed in materials as keeping the dispersion state, when Laponite XLG clay of PAANa polymer was used as the material for fixation.3) The gold nanoparticles were prepared in water-soluble polymer solution in comparison with clay gel. Gold ion was only adsorbed on poly 2-vinlpyridine (P2VP), which is a cationic polyelectrolyte. The anionic colloidal gold, however, was adsorbed on both P2VP and sodium polyacrylate (PAANa), although PAANa an anionic polyelectrolyte. The concentration and average molecular weight of polymer were found to affect the particle size and the formation rates of colloidal gold. Less