With ammonium bitartrate as templating agent and ammonia water as the negative catalyst, SiO₂-nanotubes were synthesized by hydrolysis and polycondensation of tetraethyl orthosilicate (TEOS). The groups of —CH＝CH₂ were grafted on the surface of SiO₂-nanotubes successfully by the surface modification with silane coupling agent (KH-570) to improve the surface function. The morphology structure and surface modification performance of SiO₂-nanotubes were examined by scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectrometer (FT-IR). The results confirmed that the pH of the templating agent was the primary factor affecting the morphology of SiO₂-nanotubes and the optimized pH is between 4.5 and 5.0. The diameters of tubes are uniform, and average outer and inner diameter of the SiO₂-nanotubes are 300 and 100 nm, respectively. The lengths are over 10 μm. Smooth surface of the SiO₂-nanotubes without obvious disfigurements was observed. The SiO₂-nanotubes have amorphous structure. The morphology of nanotubes remained unchanged by modification with KH-570.

Key words: SiO₂-nanotubes, synthesis, modification, characterization