Self assembly of SiO2-encapsulated carbon microsphere composites

SiO2 was firstly coated onto the surface of carbon microspheres (CMSs) using tetraethyl orthosilicate (TEOS) as precursor by Stöber method. Then SiO2-encapsulated CMS (CMS@SiO2) composites were self-assembled by vertical deposition, in which the effects of deposition temperature and suspension concentration on the quality of self-assembling film were investigated. Morphologies and structures of the samples were characterized by field emission scanning electron microscopy, Fourier transformation infrared spectrometry, X-ray diffraction and thermogravimetry. The results show that uniform CMS@SiO2 composites with good mono-dispersion were prepared by Stőber method with 0.5 g of CMSs, 2 mL of TEOS, 30 mL of ammonia and 12 h of reaction time, the CMSs-based films with ordered and denser structure were prepared by vertical deposition using CMS@SiO2 composites as monodipersion spheres under suspension concentration of 1 wt% and deposition temperature of 50 °C. The ultraviolet-visible absorption measurement shows that the absorbance of CMS@SiO2 composite films grew steadily with increasing suspension concentration.