Improvement of the quality of silica colloidal crystals by controlling drying

Nearly monodisperse SiO2 colloidal submicrospheres were prepared by hydrolysis and condensation of tetraethoxysilane. The silica colloidal crystals were prepared through natural sedimentation of silica submicrospheres in aqueous suspension. The sediments were dried separately at different temperature points before sintering treatment. The results showed that the drying temperature could greatly influence the quality of silica colloidal crystals. The silica colloidal crystals dried at 323 K had fewer defects and better optical properties. When the drying temperature was set at 323 K, the maximum attenuation of the gaps (Imax / Imin) in the transmission spectra of colloidal crystals was 109.6, which was a remarkable value of the silica colloidal crystal prepared by natural sedimentation.