Synthesis of Novel UV-Shielding Materials by Flame Aerosol Process

Abstract

Zinc oxide (ZnO) is widely used in cosmetics as a UV protection agent to shield the human body from ultraviolet (UV) radiation. However, its low acid resistance poses a challenge, as it tends to degrade on the weakly acidic human skin. In this study, titanium dioxide/zinc oxide (TiO₂/ZnO) composite particles were synthesized using a flame aerosol process to enhance the acid resistance of ZnO. The synthesized particles exhibited a uniform distribution of titanium and zinc atoms within each particle, indicating titanium dioxide existing in an amorphous state. Acid resistance evaluation through a sulfuric acid drop test confirmed that the elution of Zn²⁺ was suppressed, and the acid resistance of ZnO improved upon compositing with TiO₂. Furthermore, increasing the amount of TiO₂ in the composite further enhanced the acid resistance. These TiO₂/ZnO composite particles demonstrated potential for application as UV protection agents in sunscreen cosmetics due to their broad UV absorption properties.

Graphical Abstract

SEM images of xTi/ZnO prepared at various TTIP concentration.