Suzhou airgel nano field where the phase change material composite stealth won progress

According to Stefan-Boltzmann\’s law, and the emission of radiant energy per unit area is proportional to the fourth ratio and the thermodynamic temperature. Thus, infrared camouflage can be achieved by adjusting the temperature-controlled or infrared emissivity. For example, manufacturing a microstructure having a special surface can be changed infrared emissivity of the target, but does not impart a microstructure infrared emissivity of the target adjustable. Quantum wells, electrochromic dye, phase change material or the like can dynamic control of infrared radiation, however, usually require continuous power during the tuning 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. Researchers Suzhou Institute of Nanotechnology and Nano-bionics, CAS Zhang led with Aerogels teams having a high porosity (98%) and high specific surface area (365.99 m2 / g) prepared a flexible gas condensate plastic film, a sol is obtained by dissolving the nanofiber of Kevlar DuPont (TM), then knife coating, by sol – Kevlar airgel film gels and subsequent freeze-drying process is obtained. The airgel has excellent heat insulating properties, at room temperature, a thermal conductivity of about 0.036 W / m · K, 200μm thick airgel film over the heat source to 300 ° C, the surface temperature of only airgel 220 ° C, the temperature difference reached 80 ° C. And polyethylene glycol complex phase change material and the hydrophobic treatment, was prepared airgel / phase change composite film, composite film of the phase change: (1) a phase change enthalpy of up to 179.1 J / g; (2) with infrared emissivity most environmental context matching; (3) with ultra-low infrared transmittance in the infrared band 3μm-15 μm. In outdoor environments (e.g., light), covering an object with a non-heat the composite film, can realize the infrared stealth. Continued heating the object (such as engine), airgel insulation layer is proposed in combination with the structural phase transition superposed composite film: Kevlar airgel film having excellent heat insulating properties, depending on the temperature difference between the target and the environment, select suitable airgel layer thickness or number of layers, the temperature can be lowered to match the ambient temperature; phase-change composite film having a low infrared transmittance, the infrared light emitted can not be the target temperature transmission. This combination of high temperature and thus cover the target structure in the infrared photograph canImplementation of Infrared Stealth. The usage scenario, a matched airgel / phase change composite film or a composite structure, can be realized infrared camouflage, as shown in FIG. Research results to Nanofibrous Kevlar Aerogel Films and Their Phase Change Composites for Highly Efficient Infrared Stealth in the title, it has been published online in the international journal ACS Nano (ACS Nano 2019,13, 2236-2245), and was named ACS Editors\’ Choice Article. Preparation of 苏州纳米所在气凝胶相变隐身复合材料领域获进展 凯夫拉纳米 fibers airgel film, with a schematic view of a composite structure and phase change material Stealth