Photo credit: www.sciencedaily.com
Innovative Sunscreen Formula Offers Enhanced Protection Against UV Light and Heat
Sunscreen remains a critical element in safeguarding skin against the detrimental effects of ultraviolet (UV) radiation. While traditional formulations do provide some protection, they do not address the cooling of the skin. Recent research published in ACS’ Nano Letters has introduced a novel sunscreen that not only shields against UV rays but also utilizes radiative cooling technology to lower skin temperature. The prototype developed can maintain skin temperatures up to 11 degrees Fahrenheit (6 degrees Celsius) cooler than unprotected skin, and approximately 6 degrees Fahrenheit (3 degrees Celsius) cooler compared to current sunscreen products.
Radiative cooling is a process that either deflects or dissipates heat away from surfaces, effectively lowering the temperature of the objects beneath. This technology has found applications in various sectors, including the creation of cooling fabrics and external coatings for energy-efficient buildings. Many existing passive radiative cooling solutions leverage titanium dioxide (TiO2), a compound known for its heat-reflecting properties. Although TiO2 is effective for UV protection in mineral sunscreens, its particles typically lack the ideal size to facilitate a cooling effect. Consequently, researcher Rufan Zhang and their team focused on optimizing the dimensions of TiO2 nanoparticles to develop a dual-action sunscreen that serves both as a UV barrier and a cooling agent.
The formulation crafted by the research team consists of six components: TiO2 nanoparticles, water, ethanol, moisturizing agents, color pigments, and polydimethylsiloxane, a silicone polymer widely utilized in cosmetic products. By meticulously fine-tuning the size of the TiO2 nanoparticles, they succeeded in creating a substance capable of reflecting both UV radiation and solar heat, thus enhancing cooling properties. The resulting sunscreen showcases a sun protection factor (SPF) of approximately 50, is water-resistant, and has been shown to remain effective after 12 hours of exposure to simulated sunlight from a xenon lamp. Notably, the sunscreen demonstrated no irritation when applied to both animal and human skin.
In trials conducted in a warm and humid outdoor setting, participants using the new radiative cooling sunscreen experienced skin temperatures that were 10.8 degrees Fahrenheit (6.0 degrees Celsius) cooler than those without any sunscreen, and 11.0 degrees Fahrenheit (6.1 degrees Celsius) cooler than those using standard commercial sunscreens. Cost-effectively, the new formulation is priced at just $0.92 for a 10-gram supply, aligning it with the price range of existing products. Researchers are optimistic about the commercial viability of this sunscreen prototype, particularly as global temperatures continue to rise during the summer months.
The authors of the study credit their research to funding from the National Key Research Program, the National Natural Science Foundation of China, and the Tsinghua-Toyota Joint Research Fund.
Source
www.sciencedaily.com