Design of a Dual-Action Aerogel Film with Enhanced Radiative Cooling and Moisture Permeability through Pore Size Modulation for Human Heat and Humidity Comfort

Human thermal management technologies based on radiant cooling can achieve portable, lightweight, long-lasting, and zero-energy cooling. However, in a high-temperature environment, perspiration continues to accumulate and increased humidity reduces the efficiency of radiant cooling, thus affecting human thermal and humidity comfort. Therefore, we developed a radiation-cooled aerogel film with easily tunable pore sizes consisting of cellulose acetate, polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP), and aluminum oxide (Al₂O₃), which has excellent optical properties, moisture permeability, and thermal stability. The appropriate pore size distribution and porosity not only enhance the solar reflectivity of the film but also improve its surface wettability. High solar reflectance (R̅_solar = 97.4%) and infrared emissivity (ε̅_IR = 98.5%) enabled the film to produce subambient cooling of 8.1 °C at an irradiance of 794.1 W/m². Furthermore, even under conditions of high humidity (relative humidity = 90%), the film is expected to achieve a maximum daytime cooling power of 57 W/m². The aerogel film exhibited superior moisture permeability (WVT = 7224 g/m²·24 h) compared to commercial cotton fabric. This work has significant applications in the management of human heat and humidity in extreme heat environments.