Multifunctional Face Mask with Daytime Passive Cooling Based on PVDF/Metal–Organic Framework Hybrid Fabric

Passive daytime radiative cooling (PDRC) fabrics require no additional energy input and exhibit promising potential for outdoor cooling. Besides, multifunctional integration is urgently required for practical applications. Herein, a composite fabric based on poly(vinylidene fluoride) (PVDF) and UiO-66 was successfully prepared via combining electrospinning and in situ growth techniques. This composite fabric exhibits integrated functional properties, including passive cooling, respiratory monitoring, and smoke filtration. To achieve passive cooling dominated by radiative cooling, the prepared fibrous fabric is required to possess positive optical properties: a solar reflectance of 93.78% in the 0.3-2.5 μm infrared spectral range and an emissivity of 92.72% in the 8-13 μm mid-infrared band. The outdoor test is conducted in which the relative air humidity is 75% RH, the temperature ranges from 23 to 34 °C, the wind speed is 2.4-3.3 m/s, and the solar radiation measures 846 W m^-2; the temperature of the composite fabrics exhibits 18.7 °C lower than ambient temperature. Upon fabrication into a cooling face mask, the fabrics achieve a 5.5 °C temperature reduction compared to a conventional nonwoven mask. In addition, in a hot and humid environment, the hydrophilic properties of UiO-66 enhance the fabric's sweat absorption capacity and promote efficient evaporative cooling. Finally, the fabrics functionalized with UiO-66 particles successfully integrate the dual functions of smoke filtration and respiratory monitoring, meeting the diverse functional and practical needs of wearable fabrics.