Surface-Modified TiO₂@SiO₂ Nanocomposites for Enhanced Dispersibility and Optical Performance to Apply in the...

The grafted modification TiO₂@SiO₂ composite was fabricated by a liquid-phase deposition method with Na₂SiO₃ and a grafting reaction with a silane coupling agent. First, the TiO₂@SiO₂ composite was prepared, and the effect of deposition rate and silica content on the morphology, particle size, dispersibility, and pigmentary property of TiO₂@SiO₂ composites was investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, energy-dispersive X-ray spectroscopy (EDX), X-ray photoelectron spectroscopy (XPS), and ζ-potential. The islandlike TiO₂@SiO₂ composite had a good particle size and printing performance compared with the dense TiO₂@SiO₂ composite. The presence of Si was confirmed by EDX elemental analysis and XPS, and a peak at 980 cm^-1 belonging to Si-O was observed in the FTIR spectrum, confirming the presence of SiO₂ anchored at TiO₂ surfaces via Si-O-Ti bonds. Then, the islandlike TiO₂@SiO₂ composite was modified by grafting with a silane coupling agent. The effect of the silane coupling agent on the hydrophobicity and dispersibility was investigated. The peaks at 2919 and 2846 cm^-1 belong to CH₂ in the FTIR spectrum, and Si-C in the XPS confirmed the grafting of silane coupling agent to the TiO₂@SiO₂ composite. The grafted modification of the islandlike TiO₂@SiO₂ composite using 3-triethoxysilylpropylamine endowed it with weather durability, dispersibility, and good printing performance.