Sunscreen Composed of Nanofiber with Enhanced UV Protection and Thermal Comfort for Human Skin

Prolonged ultraviolet (UV) exposure can cause various skin issues. In this study, a nanofiber membrane composed of electrospun polyvinylidene fluoride (PVDF), reinforced with polyurethane (PU) nanofibers, is presented to enhance UV scattering and reflection with mechanical stability and high skin adhesion. The membrane exhibits ≈20% visible transparency while efficiently reflecting UV radiation, providing both effective UV protection and improved thermal comfort surpassing conventional sunscreens that primarily rely on UV absorption. Fiber diameter and density are optimized to have an average fiber diameter of 84.5 nm to maximize UV scattering over visible scattering. The optical properties of the membrane demonstrates exceptional UV reflectance, averaging 91.79% in the UVB region and 84.52% in the UVA region. The UV-blocking efficiency per unit mass of the nanofiber membrane is around five times higher than that of conventional UV-absorbing sunscreens. Furthermore, the thermal cooling performance of the nanofiber membrane is further assessed in a humidity chamber under a solar simulator and compared against conventional sunscreens, revealing a surface temperature ≈1 °C cooler than that of skin treated with the conventional sunscreens. These findings offer new perspectives for nanofiber-based UV protection technologies as advanced sunscreens with promising UV shielding and thermal regulation.