Dual-functional reduced graphene oxide decorated nanoporous polytetrafluoroethylene metafabrics for radiative cooling and solar-heating†

Although passive radiative cooling and active heating are becoming two essential functions for next-generation smart personal thermal management textiles, the integration of opposite cooling and heating into one metafabric with great wear comfort and multi-environmental adaptability is still challenging. Herein, a dual-functional reduced graphene oxide (RGO) decorated nanoporous polytetrafluoroethylene (PTFE) metafabric with a unique sandwich structure is designed for multi-scenario personal thermal management. By assembling a spectrum-selective nanoporous PTFE radiative cooling substrate with a solar-thermal and highly emissive RGO layer and a visibly transparent polydimethylsiloxane supporting coating, opposite cooling and heating functions are integrated into the sandwich-structured metafabric. The resultant metafabric exhibits spectrum-selective properties with both high solar spectrum reflectivity (>90%, 0.25–2.5 μm) and high transparency in the human body infrared radiation range (>90%, 7–14 μm). For radiative cooling at an ambient temperature of 36 °C, the metafabric can dissipate thermal radiation from the skin and prevent solar radiation heat through the outermost visible reflective nanoporous PTFE layer, achieving radiative cooling with a 3.2 °C temperature drop compared to traditional cotton cloth. Whereas for solar heating, the metafabric can convert solar radiation to heat through the outside RGO layer, keeping a warmer surface microclimate, which is 17.0 °C higher than that of traditional cotton cloth in a 0 °C cold environment. By flipping the obverse and reverse sides of the metafabric, the radiative cooling and the solar-heating modes can be easily switched to adapt to various scenarios. Meanwhile, the dual-functional metafabric exhibits remarkable wearable performances because of its flexibility, moisture permeability, water-proofness, anti-fouling, and flame-retardancy.