Investigation of surface modification of rutile TiO2 nanoparticles with SiO2/Al2O3 on the properties of polyacrylic composite coating

• SiO2/Al2O3 was successively coated on the surfaces of rutile TiO2 nanoparticles.
• The average particle size of nanoparticles is dispersion's solid content dependent.
• IEP for TiO2–SiO2/Al2O3 is at lower pH than for TiO2 nanoparticles.
• TiO2–SiO2/Al2O3 in polyacrylic clear coating shows efficient UV absorption.
• TiO2–SiO2/Al2O3 in a coating shows higher transparency compared to TiO2.

Surface modification and characterization of TiO2 nanoparticles as an additive in a polyacrylic clear coating were investigated. For the improvement of nanoparticles dispersion and the decreasing of photocatalytic activity, the surface of nanoparticles was modified with binary SiO2/Al2O3. The surface treatment of TiO2 nanoparticles was characterized with FTIR. Microstructural analysis was done by AFM. The size, particle size distribution and zeta potential of TiO2 nanoparticles in water dispersion was measured by DLS method. For the evaluation of particle size and the stability of nanoparticles in water dispersions with higher solid content the electroacoustic spectroscopy was made. To determine the applicability and evaluate the transmittance of the nano-TiO2 composite coatings UV–VIS spectroscopy in the wavelength range of 200–800 nm was employed. The results showed that surface treatment of TiO2 nanoparticles with SiO2/Al2O3 improves nanoparticles dispersion and UV protection of the clear polyacrylic composite coating.