PERFORMANCE OF SILICON ALUMINUM COATED NANO TITANIUM DIOXIDE FILM ON OIL PAINTING PIGMENTS

This study aims to address the strong hydrophilicity, poor dispersibility, and insufficient weather resistance caused by photocatalytic activity when nano TiO2 is used as a film for oil painting pigments.A silicon aluminum composite coating modification strategy is proposed, and a SiO2/Al2O3@TiO2 composite structure is constructed by water bath layer by layer coating method.The impact of this strategy on the performance of oil painting pigments is systematically analyzed.The experiment used ethyl orthosilicate and aluminum sulfate as precursors, and achieved layer by layer deposition of silicon and aluminum oxides on TiO2 surface through pH regulation.The characterization results showed that the SiO2/Al2O3 composite coating layer (thickness: 3-4 nm) significantly improved the surface charge stability of TiO2, with a Zeta potential of -33.0 mV at pH 9-10, and a 30% decrease in UV absorption intensity compared to uncoated TiO2, effectively suppressing photocatalytic activity.The water-based oil painting pigment prepared based on modified TiO2 showed an increase in whiteness to 97.4% (1.1% higher than the uncoated sample).The glossiness at 60 reached 49.7% (an increase of 10% compared to the uncoated sample), the covering power increased to 12.0 g/cm, and the water resistance was significantly enhanced.The research shows that the silicon aluminum bilayer coating not only optimizes the optical properties and dispersibility of TiO2 through complementary acid-base stability and interface synergy, but also endows the pigment with excellent weather resistance and mechanical stability, providing new ideas for the development of high-performance and environmentally friendly oil painting pigments.