The original airgel material is not only light and warmth, you can also do \”cloak of invisibility\”
Stealth technology is to improve the weapons, equipment and personnel survivability and combat effectiveness in the war environment and developed an important military technology. Wherein the infrared camouflage can be achieved by adjusting the temperature-controlled or infrared emissivity. For example, a quantum well, an electrochromic dye, phase change materials can be dynamic control of infrared radiation, however, usually require continuous power consumption in the entire process, and a slow response speed, a narrow tuning range, poor flexibility. Further, by regulating the temperature infrared camouflage can be achieved, however, thermal blankets and other materials are generally relatively heavy, easily lead to heat build-up. Visible, effectively hiding the target, it is not visible to the thermal infrared detectors still faces enormous challenges. Aerogels having an ultra-low density, high continuous porosity, surface area larger than a synthetic material, has extremely important application in heat insulation, sound insulation, water purification, and other fields of membrane separation value. At the same time, it is also used airgel nano phase change material to improve its thermo-physical properties, while maintaining its storage capacity, and therefore thealso has the broad application prospect in the infrared stealth insulation. Based on this, having a high porosity (98%) and high specific surface area (365.99 m2 / g) of Nano Nano Technology Institute, Chinese Academy of aerogels bionic team prepared the flexible airgel film . They nanofiber obtained by dissolving a sol of Kevlar DuPont (TM), then knife coating, by sol – Kevlar airgel film gels and subsequent freeze-drying process is obtained. Kevlar preparation of aerogels of the airgel phase change film having excellent heat insulating properties, at room temperature, a thermal conductivity of about 0.036 W / m · K, 200μm thick airgel film covering in the heat source to 300 ° C, the surface temperature of the airgel is only 220 ° C, the temperature difference reached 80 ° C. Kevlar airgel film appearance and Characterization of the airgel film (KNA) and the phase change material, polyethylene glycol (PEG) and the hydrophobic treatment composite prepared airgel / phase change composite film. The phase change composite film has the following advantages: (1) a phase change enthalpy of up to 179.1 J / g; (2) Infrared emissivity match with most environmental context; (3) with ultra-low infrared transmittance in the infrared band 3 ~ 15μm. In outdoor environments (e.g., light), with the composite film coverAfebrile cover object may be achieved IR stealth.
stealth composite film under the effect of outdoor conditions
Meanwhile, the research team conclusions airgel insulation layer and the structural phase transition in combination to achieve the composite film superposed infrared heating object stealth: Kevlar airgel film have excellent insulation properties, depending on the temperature difference between the target and the environment, to select an appropriate number of layers or thickness of the airgel layer, the temperature can be lowered to match the ambient temperature; phase-change composite film having a low infrared transmittance, infrared light can not pass through the high temperature emission targets. Thus covering the objectives of this high-temperature composite structure in the infrared photograph can achieve stealth. airgel insulation layer and the phase-change composite film synergistic IR stealth