Dual-Mode Polyimide Composite Membrane with a Hierarchical Structure for Passive Thermoregulation

Smart thermoregulating textile has gained more and more attention due to its green and sustainable property with zero energy consumption. Passive heating and cooling of smart textiles responding to dynamic weather changes is a key issue to be resolved. Herein, based on the chemical design, we demonstrate a polyimide nanofiber (PINF) membrane via the electrospinning method by incorporation of fluorine-containing and aliphatic structures, and the resultant dual-mode polyimide@polypyrrole (PINF@PPy) composite membrane can be obtained with subsequent decoration by PPy. The sunlight reflection of cooling and heating sides of dual-mode composite membranes is ∼87.5% and ∼11.6% in wavelengths of 0.4–2.5 μm, respectively, which contributes to the temperature drops of ∼4.1 °C and increasement of ∼10.0 °C, exhibiting excellent passive dual-mode thermoregulating performance. The composite membrane has no obvious weight loss before ∼348.7 °C, exhibiting an ideal thermal stability. Additionally, it can be easily switched between cooling and heating modes by flipping the membrane, allowing it to keep the body comfortable with temperature fluctuations and contribute to reducing greenhouse gas emissions.