**4. Conclusion and prospects**

As a critical pigment, TiO2 has a considerable application market. However, due to the crystal defects, there is a photocatalytic active site on the surface of TiO2. After absorbing ultraviolet light, free radicals are produced, causing organic compound degradation in the surrounding TiO2. Besides, TiO2 particles are easy to agglomerate

and are dispersed poorly in the organic matrix due to the high specific surface area. The surface inorganic/organic modification of TiO2 is an excellent choice to overcome the drawbacks of TiO2. The coating films on the surface of TiO2 can effectively inhibit the oxidative degradation of the organic matrix and improve the dispersion of TiO2, finally improving pigmentary properties of TiO2, such as whiteness, hiding power, light resistance, and weather resistance. With the development of the economy, the demands for applying TiO2, such as high weather resistance, light resistance, and dispersion stability, are gradually increased. Thus, the coating treatments of TiO2 are an essential strategic development direction in the future.
