March 19, 2025 – Titanium dioxide (TiO2), commonly known as “titanium white,” is a white solid or powder form of amphoteric oxide. Renowned for its exceptional opacity, remarkable whiteness, and dazzling brightness, TiO2 is not only odorless and non-toxic but also non-flammable, insoluble in water, hydrochloric acid, and various organic solvents. These unique physicochemical properties have made titanium dioxide shine in multiple fields, particularly in the cosmetics industry, where its applications are both extensive and profound. From serving as a physical sunscreen to protect the skin from UV rays, to acting as a concealer for flawless foundation, and even as an oil-absorbing ingredient to keep powder products fresh, TiO2 plays an irreplaceable role. Additionally, it functions as a colorant, adding rich hues to products.
In nature, titanium dioxide coexists in three crystalline forms: anatase, rutile, and brookite. However, due to its limited natural occurrence and restricted applications, brookite is seldom used in practical applications. Instead, anatase and rutile have become the mainstream. Although both share an octahedral structure characteristic of titanium dioxide, they exhibit distinct physical properties due to variations in octahedral deformation and arrangement. It is understood that rutile tends to align more closely with a tetragonal crystal system, while anatase undergoes more significant deformation, resulting in lower symmetry compared to the tetragonal system. This structural disparity directly leads to differences in mass density and electronic band structure, making rutile more stable and dense. In contrast, anatase demonstrates higher reflectivity in the short-wave visible light spectrum but has weaker UV absorption capabilities. Under specific conditions, such as when the temperature reaches 500℃, anatase can transform into rutile.
Nano-titanium dioxide, a special form of titanium dioxide, maximizes UV protection performance. It not only absorbs UV rays but also effectively reflects and scatters them while maintaining high transparency to visible light. As a result, it is hailed as a high-performance, promising physical shielding UV protectant. The particle size of nano-titanium dioxide is much smaller than the wavelength of visible light, which minimizes its scattering effect on visible light, ensuring high transparency in products. Its strong scattering and absorption of UV rays lay a solid foundation for its sunscreen properties. Furthermore, nano-titanium dioxide exhibits certain antibacterial capabilities, primarily due to its photocatalytic activity and its ability to kill bacteria and fungi. However, the application of nano-titanium dioxide in sunscreen products also faces numerous challenges, such as the formation of agglomerates, high production costs, and environmental impacts. In the future, with the optimization of production processes, reduction in costs, and in-depth research into environmental impacts, the application prospects of nano-titanium dioxide in sunscreen products will become even broader.