Synthesis of disperse amorphous SiO2 nanoparticles via sol–gel process

Disperse amorphous SiO2 nanoparticles are essential to the preparation of SiO2 nanoglass. In our present work, disperse fine amorphous SiO2 nanoparticles with a narrow size distribution were synthesized by a sol-gel method and subsequent calcination. In the synthesis, polyethylene glycol 1000 (PEG 1000) was used as surfactant, tetraethyl orthosilicate (TEOS) as silicon source, and ammonia as catalyst. The size and morphology of amorphous SiO2 nanoparticles were tuned by adjusting the amount of PEG 1000. At 0.1 g PEG 1000, large SiO2 nanoparticles with an average size of 35 nm most of which are agglomerated and catenulate in shape were produced. At 0.05 and 0.0125 g, SiO2 nanoparticles with an average size of 18 nm which are nearly disperse with weak agglomeration and irregular in shape were obtained. Under the optimum condition of 0.025 g PEG 1000 and after calcination at 800 °C for 10 h, SiO2 nanoparticles prepared are completely disperse without any agglomeration, fine, and equiaxed in shape and have an average size of 9 nm and a size distribution of 4–18 nm.