Synthesis and characterization of a broad-spectrum TiO2@lignin UV-protection agent with high antioxidant and emulsifying activity

TiO2 with biocompatibility and low price was limited application in cosmetics due to its narrow UV protection range, producing free radicals under UV irradiation to accelerated skin aging and whitish. Herein, a series of highly effective broad-spectrum TiO2@lignin sunscreen microscopes (TWLx) were prepared by modulating van der Waals forces and hydrogen bonding interactions between TiO2 and lignin. The results showed that the UV main absorption peak of TWLx increased from UVA to UVA + UVB. TWLx could completely eliminate the hydroxyl radical produced by TiO2 under UV irradiation owe to introduction of lignin. Meanwhile, the combination of TiO2 and lignin could neutralize color, which made TWLx color closer to human skin. The UV-protection test showed that the SPF value of sunscreen containing 3 wt% TWLx reached 137.4. The antioxidant experiment showed that TWLx has about 16 times the DPPH radical scavenging ability of TiO2. Finally, high internal phase Pickering emulsions were prepared by using TWLx as a stabilizer. It was found that the internal phase volume fraction of the emulsion was up to 86 vol%, which could be recognized as the highest internal phase reported in suntan lotion. This work would provide new ideas for the synthesis of highly effective broad-spectrum sunscreens.