Nanoparticles are commonly used to avoid the opaque white color of TiO2 based sunscreen. However, a dispersing agent is typically required because of the tendency of the nanoparticles (NPs) to agglomerate. Stearic acid is one kind of dispersing agent often used for sunscreen products. However, according to the MSDS data sheet on stearic acid, stearic acid is highly hazardous to aquatic life and causes irritation on human skin. To avoid this problem, in this study a safer organic dispersing agent extracted from Korean seaweed has been studied to disperse TiO2 nanoparticles, and further use as an active agent in sunscreen products. The presence of phytochemicals in seaweed extract, especially alginate, can disperse TiO2 nanoparticles and improve TiO2 dispersion properties. Results show that seaweed extract can improve the dispersion properties of TiO2 nanoparticles and sunscreen products. Reducing the agglomeration of TiO2 nanoparticles improves sunscreen properties, by making it less opaque white in color, and increasing UV protection value. It was also confirmed that adding seaweed extract into sunscreen products had no irritating effects on the human skin, making it more desirable for cosmetics application.

1. Introduction
2. Experimental Procedure
    2.1. Seaweed extracts preparation
    2.2. TiO2 suspension for sunscreen products preparation
3. Results and Discussion
    3.1. Effects of seaweed extract on dispersibilityproperties of TiO2
    3.2. Effects of seaweed extract on sunscreen properties
    3.3. Skin patch safety evaluation
4. Conclusion
Availability of Data and Materials
Acknowledgement
Ethics Approval
References
Author Information

• Pestaria Sinaga(Department of Mechatronics Engineering Kyungnam University, Changwon 51767, Republic of Korea)
• Sung-Hwan Bae(Materials Science and Engineering, Kyungnam University, Changwon 51767, Republic of Korea) Corresponding author