Study on the application and performance of liquid crystal emulsion system in sunscreen products

Liquid crystal (LC) emulsion is a new emulsion system which has excellent application potential in the field of cosmetics. In this study, the LC emulsifier and traditional emulsifier were used to prepare the emulsions containing different types of sunscreen agents, respectively. The microstructure, sunscreen performance and rheological properties of the emulsions were studied systematically. The results showed that the formation of LC structure was not affected by sunscreen agents. LC structure can also enhance the sunscreen property of the emulsion as well as improve the sensory property. Further, we combined different sunscreen agents to prepare LC sunscreen emulsion. The sunscreen performance and repair effectiveness of emulsion were evaluated by human test. The results showed that LC sunscreen emulsion has an increased SPF value from 56 to 70 compared to non-LC sunscreen emulsion. Meanwhile, the LC structure also enhanced the moisturising properties of the emulsion, and the TEWL value of LC emulsion and non-LC emulsion was 67.4% and 96.5%, respectively. In addition, LC sunscreen emulsion has higher safety and better storage stability. In conclusion, this study provided the practical application of LC emulsion systems as well as the important guidance for developing excellent sunscreen emulsions.