油性介质中组装二氧化硅胶体晶体薄膜

PREPARATION OF SILICA COLLOIDAL CRYSTAL FILMS BY USING OILINESS DISPERSANT

报道了一种由粒径大于700 nm的SiO2微球组装胶体晶体薄膜的方法.以一种密度较大的疏水性有机物替代水或醇类为分散剂,通过对SiO2微球表面进行疏水性处理改善其在油性介质中的分散性,采用改进的垂直沉积法在油性分散剂中制备SiO2胶体晶体.用扫描电子显微镜、红外光谱仪和紫外-可见光谱仪对SiO2胶体晶体薄膜的形貌、结构和光学性能进行了观察测试.结果表明:较大密度的分散剂能有效降低SiO2微球的沉降速度,组装成直径在700～2 000 nm范围的SiO2微球的胶体晶体.获得的SiO2光子晶体具有长程有序结构,并在近红外区具有显著的光子频率带隙.

A modification method of vertical deposition was proposed to synthesize colloidal crystal films composed of silica spheres with diameters larger than 700 nm. Instead of using water or alcohol as dispersant, a hydrophobic organic compound was used. With appropriate surface chemical modification, the surfaces of silica spheres were treated by hydrophobe in order to improve their dispersivity in the hydrophobic compound. Then, colloidal crystal films were prepared in an oily dispersant by vertical deposition. The SiO2 colloidal crystal films obtained were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy. The results show that the settlement of spheres was obviously slowed down by using an oily compound with larger density as dispersant, and colloidal crystal films with silica spheres from 700 nm to 2 000 nm were obtained. It was found that the samples had long ordered structures and photonic band gaps in the near-infrared region.