Electrochromic\nCovalent Organic Framework-Assembled\nNanofibrous Membranes with Mimetic Chameleon Skin Architectures for\nVisible and Near-Infrared Camouflage Stealth

The developments of modern surveillance technology pose\ngreat challenges\nto combat concealment for warfighters. Traditional camouflage suits\ncannot accommodate the need for camouflage stealth in complex warfare\nscenarios. Herein, a bidirectional diffusion-controlled in situ synthesis\nmethodology is reported to achieve electrochromic nanofibrous membranes\nwith mimetic chameleon skin structures (CSENs) by assembling electrochromic\ncovalent organic frameworks on nanofibers. CSENs exhibit reversible\ncolor changes in the visible and near-infrared ranges under an applied\npotential with fast response times (25.8 s/26.2 s). The macro- and\nmesoporous structures in CSENs favored the transportation of electrolyte\nions, achieving excellent color difference and coloration efficiency\nof 35.58 and 1053.26 cm<sup>2</sup>/C, respectively. Importantly,\nCSENs feature unique properties of self-standing, breathability, and\nflexibility, which are attributed to the micrometer pores constructed\nby entangled nanofibers. As a proof-of-concept study, the CSEN-based\nflexible electrochromic suit exhibits a dynamic camouflage function\nin real environments, showing promising properties as smart textiles\nfor dynamic camouflage stealth.