嵌段共聚物反介观液晶相新方法合成多级有序排列的二氧化硅纳米棒

在非极性溶剂体系中,开辟了利用反相液晶法制备多级有序纳米材料的新方法.利用嵌段共聚物表面活性剂在非极性溶剂中形成反相胶束,无机硅物种可以进入胶束的内部,在溶剂挥发后,有机-无机物种进一步组装成为反相六方液晶相.除去模板剂后即制备出尺寸规则的二氧化硅纳米棒材料.由于嵌段高分子的作用,六方排列的二氧化硅纳米棒进一步排列成层状结构(层间距约150nm).通过选择表面活性剂及改变其浓度,纳米棒的尺寸可以在9～15nm范围内调变.该反应途径对于合成其它尺寸均一、多级有序排列的纳米棒材料是非常有意义的.

Synthesis of Hierarchically Arrayed Silica Nanorods via Reverse Amphiphilic Block Copolymer Mesophases

A reverse amphiphilic mesophases approach to create hierarchically arrayed silica nanorods has been demonstrated. In nonpolar solvent systems, the cylinder nanorods with a uniform diameter(10 nm) generated from highly ordered two-dimensional(2D) reverse hexagonal mesophases are aligned within lamellar macrostructures(~150 nm). The diameter size of silica nanorods can be adjusted from 9 to 15 nm by varying the chain length of the EO segment and the concentration of the surfactants. Low surfactant concentration and long hydrophilic EO segment chain yield silica nanorods with a large diameter. The calcined material has a relatively small surface area of 275 m 2/g. This approach may provide a new pathway to the fabrication of nano-objects that might be applied in nanoscale devices.