Infrared stealth nanofibrous composites with thermal adaptability and mechanical flexibility

Abstract Thermal adaptability is one of the key parameters for infrared stealth materials regarding the applications in infrared camouflage and energy saving aircrafts and buildings. By employing polyacrylonitrile (PAN) as the polymer matrix, antimony doped tin oxide (ATO) and vanadium dioxide (VO2) as the fillers, fibrous membrane composites of ATO/PAN-xVO2 (x =0, 20, 40, and 60 mol %) are prepared by electrospinning followed by sintering. The infrared stealth performances including the emissivity and infrared images, as well as the uniaxial stress-strain relationship of the fibrous membranes are characterized. At the temperature range of 25–90 °C, the infrared emissivity ( e ) decreases continuously for ATO/PAN (ATO/PAN-0VO2) membrane, while there is an abrupt drop around 68 °C for ATO/PAN-xVO2 (x = 20, 40, and 60 mol %) membranes. The infrared images taken at different temperatures further verifies the infrared stealth performance for the four fibrous composites. Due to the thermistor behavior of ATO, with the temperature rising, increase in the electronic conductivity renders the composite enhanced infrared stealth performance. The abrupt drop near 68 °C for composites with VO2 is related to the phase transition of VO2 from monoclinic (semiconductor) to rutile structure (metal). The stress-strain behavior under the uniaxial tension reveals that the fracture strength and strain decrease monotonically with VO2 content increasing. Our results offer a selection of thermal adaptive materials with combined infrared stealth and mechanical behavior.