Scientists have developed a groundbreaking sunscreen that utilizes specially sized titanium dioxide nanoparticles to reflect heat and UV rays, providing both SPF 50 protection and significant cooling effects—ideal for hot summer days. This innovative formula combines UV protection with radiative cooling, keeping skin up to 11°F (6°C) cooler than bare skin and 6°F (3°C) cooler than conventional sunscreens. The sunscreen works by reflecting heat away from the skin, a principle already applied in cooling fabrics and energy-efficient coatings. The research team fine-tuned the particle size of titanium dioxide to enhance its cooling properties, resulting in a sunscreen made from six ingredients: TiO2 nanoparticles, water, ethanol, moisturizing cream, pigments, and a cosmetic silicone polymer. It demonstrated 12-hour efficacy under simulated sunlight without causing irritation on both animal and human skin. Tested in hot conditions, the sunscreen significantly outperformed standard products in terms of cooling. Priced competitively at approximately $0.92 for 10 grams, this prototype showcases strong commercial potential in response to rising global temperatures. The findings were published in ACS Nano Letters by a team funded by various research programs in China.
