A groundbreaking development in sun protection technology combines UV defense with cooling properties, offering a potential solution for staying comfortable during increasingly hot summers. This innovative sunscreen formula harnesses the power of radiative cooling to keep skin significantly cooler than traditional sunscreens while maintaining strong UV protection.
Published in Nano Letters | Estimated reading time: 4 minutes
In a significant advance for sun protection technology, researchers led by Rufan Zhang have developed a sunscreen that not only shields against harmful UV rays but actively cools the skin through a process called radiative cooling. The new formula demonstrates remarkable cooling capabilities, keeping skin up to 11 degrees Fahrenheit cooler than bare skin and 6 degrees cooler than conventional sunscreens.
The secret behind this dual-action sunscreen lies in its carefully engineered titanium dioxide (TiO2) nanoparticles. While TiO2 is a common ingredient in mineral sunscreens, the research team specifically tuned the size of these particles to optimize both UV protection and heat reflection. The result is a formula that achieves an impressive SPF 50 while incorporating radiative cooling properties – a feature absent in traditional sunscreens.
The new formulation combines six key ingredients: precisely-sized TiO2 nanoparticles, water, ethanol, moisturizing cream, pigments, and polydimethylsiloxane (a common silicone polymer used in cosmetics). Through extensive testing, the prototype demonstrated remarkable durability, maintaining its effectiveness after 12 hours of simulated sunlight exposure. Importantly, the formula showed no signs of skin irritation in both human and animal testing.
Performance testing in hot, humid outdoor conditions yielded impressive results. The sunscreen demonstrated consistent cooling effects across various summer weather scenarios, including low-humidity sunny days, high-humidity sunny days, and high-humidity cloudy days. Perhaps most encouraging for potential commercialization, the production costs remain competitive with existing sunscreens at approximately $0.92 per 10 grams.
Glossary
- Radiative Cooling
- A passive cooling process where an object either reflects or radiates heat away, cooling whatever lies beneath it without using energy.
- Titanium Dioxide (TiO2)
- A white substance commonly used in mineral sunscreens to reflect UV light, which can also reflect heat when properly engineered.
- SPF (Sun Protection Factor)
- A measure of how well a sunscreen protects against ultraviolet B (UVB) rays, with higher numbers indicating greater protection.
Test Your Knowledge
What is the approximate cost of 10 grams of the new sunscreen formula?
The new sunscreen costs about $0.92 for 10 grams, which is comparable to existing sunscreens on the market.
What is the SPF rating of the new sunscreen prototype?
The new sunscreen formulation demonstrates an SPF of approximately 50.
How many ingredients are combined to create the cooling sunscreen, and what are they?
The sunscreen combines six ingredients: TiO2 nanoparticles, water, ethanol, moisturizing cream, pigments, and polydimethylsiloxane (a silicone polymer used in cosmetics).
What specific characteristics make this sunscreen effective at both UV protection and cooling?
The sunscreen achieves its dual functionality through precisely tuned TiO2 nanoparticle sizes, resulting in a low UV transmissivity (4.86%), high solar reflectivity (90.19%), and high mid-infrared emissivity (92.09%).
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