琼脂糖凝胶中树枝状银的生长研究

以琼脂糖凝胶作为模板、还原剂和稳定剂，通过溶胶-凝胶法制备琼脂糖/纳米银复合凝胶，对所得到的银纳米粒子进行了表征. 在复合凝胶外侧使用铝箔破坏凝胶中银纳米粒子的平衡状态，实现银纳米粒子在凝胶中的聚集并生成三维树枝状结构，并对树枝状银进行了表征. 结果表明，银纳米粒子为球形，粒径在20 nm左右，分散性好. 以琼脂糖凝胶为模板生长的树枝状银形状完整，尺寸与复合凝胶的样品大小有关，可达厘米级. 树枝状银的形貌可通过改变硝酸银浓度进行调控. 树枝状银结构的形成是扩散限制凝聚的结果. 关键词:琼脂糖；银纳米粒子；树枝状银；复合凝胶；可控制备

Controlled Growth of Silver Dendrites in Agarose Gel

garose/nanosilver composite gel was prepared by sol-gel method using agarose gel as the template， the reducing agent and the stabilizer，and the obtained silver nanoparticles were characterized. Aluminum foil was used on the outsides of composite gel to alter the equilibrium state of the silver nanoparticles in the gel and to induce the aggregation of the silver nanoparticles and the formation of a three-dimensional silver dendritic structure. These silver dendrites were also characterized by optical microscopy and scanning electronic microscopy. The results show that the synthesized silver nanoparticles are spherical and homogeneous with a size of about 20 nm. The preparation process with agarose gel as template endows the silver dendrite an intact structure. The size of the silver dendrite， which depends on the dimension of the composite gel sample， can be up to several centimeters. The morphology of silver dendrites can be regulated by adjusting the concentration of the reagent silver nitrate. The formation of silver dendrites is supposed to follow the diffusion-limited aggregation mechanism.