Preparation and properties of silicon dioxide/polyaniline composite particles

Polyaniline (PANI) was formed preferentially on the surfaces of silicon dioxide particles, which resulted in PANI coated silicon dioxide composite particles (SD/PANI), when aniline (ANI) was polymerized through chemical oxidative polymerization with the presence of silicon dioxide particles. Scanning electron microscopy (SEM) and transmitting electron microscopy (TEM) examinations showed that smooth PANI layer with thickness of 10-60nm was formed with lower ANI content in reactants; while with higher ANI content, the PANI layer showed particulate appearance. UV-VIS spectra and X-ray photoelectron spectroscopic (XPS) analyses have indicated that oxidation state of PANI on the surfaces of silicon dioxide particles decreases with the content of silicon dioxide particles in reactants. PANI layer adhered firmly to the surface of silicon dioxide particle and the composite particles passivated the cold rolled steel (CRS) as the pure PANI did.