Traditional sunscreens play a critical role in protecting our skin from harmful UV radiation.
However, they usually lack a refreshing cooling effect.
In an exciting new study featured in ACS’ Nano Letters, a team of researchers has unveiled an innovative sunscreen formulation that not only defends against UV rays but also harnesses radiative cooling technology to minimize heat absorption from the sun.
Their prototype demonstrated the remarkable ability to lower skin temperatures by up to 11 degrees Fahrenheit (6 degrees Celsius) compared to untreated skin, and it was nearly 6 degrees Fahrenheit (3 degrees Celsius) cooler than standard sunscreens currently on the market.
Understanding Radiative Cooling
So, what is radiative cooling? It refers to the process of reflecting or dissipating heat, effectively lowering the temperature of the surface beneath it.
This principle has been utilized in various materials and coatings designed for temperature control, particularly in the construction sector.
An essential component for many radiative cooling applications is titanium dioxide (TiO2), which is famed for its reflective qualities.
While you’ll typically find TiO2 in mineral sunscreens for its UV-blocking abilities, its size usually doesn’t optimize the cooling benefits.
To tackle this challenge, researcher Rufan Zhang and his team focused on modifying the dimensions of TiO2 nanoparticles to enhance both UV shielding and cooling effects in sunscreen.
Innovative Formulation
The new sunscreen formulation comprises six key ingredients: TiO2 nanoparticles, water, ethanol, a moisturizing agent, pigments, and polydimethylsiloxane, a silicone polymer found in various cosmetic products.
By adjusting the size of the TiO2 nanoparticles, the researchers crafted a formula that adeptly reflects harmful UV rays while also cooling the skin.
This cutting-edge sunscreen boasts an impressive SPF of around 50, is water-resistant, and retained its protective qualities even after exposure to simulated sunlight for 12 hours under a xenon lamp.
Most notably, both human and animal skin tests indicated that this new formula caused no irritation.
Field Trials and Economic Viability
Field trials conducted in warm, humid environments revealed striking results: participants using the innovative radiative cooling sunscreen experienced skin temperatures up to 10.8 degrees Fahrenheit (6 degrees Celsius) cooler than those without sunscreen, and up to 11 degrees Fahrenheit (6.1 degrees Celsius) cooler compared to those using existing commercial options.
Impressively, the cost to produce this formulation sits at approximately $0.92 for every 10 grams—making it an economically viable choice compared to other products available in stores.
Given the trend of rising summer temperatures, the research team is optimistic about the potential success of their sunscreen in the market.
This groundbreaking research gained backing from prestigious sources such as the National Key Research Program, the National Natural Science Foundation of China, and the Tsinghua-Toyota Joint Research Fund.
Source: ScienceDaily