Liu Jia, Deng Yonghui, Liu Chong, Sun Zhenkun, Zhao Dongyuan
Department of Chemistry, Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials, Advanced Materials Laboratory, Fudan University, Shanghai 200433, PR China.
J Colloid Interface Sci. 2009 May 1;333(1):329-34. doi: 10.1016/j.jcis.2009.02.013. Epub 2009 Feb 11.
In this paper, we report a simple approach for templating synthesis of magnetic hollow composite microspheres with magnetite/silica walls. This approach is based on the co-sedimentation of polymer microspheres and magnetic colloids followed by impregnation with silica oligomer from tetraethyl orthosilicate and the further removal of the polymer microspheres by pyrolysis. The diameter of the hollow microspheres can be adjusted in range of 300 nm-2.0 microm by using polymer microspheres of different sizes and the wall thickness is tunable from 10-50 nm by controlling ratio of magnetite to the polymer microspheres. Magnetic characterizations show that the hollow microspheres have superparamagnetism with magnetization saturation of 10-30 emu/g. HRTEM and N(2) adsorption-desorption isotherms reveal that the hollow microspheres have numerous nanopores in the walls with a broad distribution in the range of 2 to 80 nm, which results in a high BET surface (67.6 m(2)/g) and pores volume (0.14 cm(3)/g).
在本文中，我们报道了一种用于模板合成具有磁铁矿/二氧化硅壁的磁性空心复合微球的简单方法。该方法基于聚合物微球和磁性胶体的共沉淀，随后用原硅酸四乙酯的二氧化硅低聚物进行浸渍，并通过热解进一步去除聚合物微球。通过使用不同尺寸的聚合物微球，空心微球的直径可在300纳米至2.0微米范围内调节，并且通过控制磁铁矿与聚合物微球的比例，壁厚可在10至50纳米范围内调节。磁性表征表明，空心微球具有超顺磁性，饱和磁化强度为10至30emu/g。高分辨率透射电子显微镜（HRTEM）和N₂吸附-脱附等温线表明，空心微球的壁上有许多纳米孔，孔径分布在2至80纳米的宽范围内，这导致了较高的比表面积（67.6平方米/克）和孔体积（0.14立方厘米/克）。
