Wearable and Breathable Electrochromic Textiles Enabled by Biomimetic Hierarchical COF Membranes for Robust Adaptive Camouflage

With continuous developments of high-tech reconnaissance systems, the visibility of weapons, equipment, and personnel on the battlefield has significantly increased, posing serious threats to soldier survival and national security. Herein, we report a facile methodology for fabricating an electrochromic microfibrous membrane (ECFM) with a biomimetic porous architecture via bidirectional diffusion-controlled in situ synthesis of electrochromic covalent organic frameworks (ECOFs) on porous microfibers. The resultant ECFM features coral-like hierarchical pores, including micrometer pores formed by fiber entanglement, submicrometer pores in the porous microfibers, and intrinsic mesopores of the ECOFs, which facilitate the transportation efficiency of electrolyte ions. Thus, the ECFM demonstrates reversible switching between yellow and black under applied voltage, with fast response times (coloration/bleaching = 13.6 s/17.8 s), remarkable color contrast (Δ<i>E</i> = 25.7), and superior coloration efficiency (154.66 cm²/C). In addition, the membrane exhibits excellent flexibility, breathability, and mechanical strength, highlighting its strong potential as a smart textile material for adaptive camouflage stealth.