The self-regulated infrared emissivity properties of BCG/MgCl2/PEG-g-CDA powders for tunable IR signals

The green BCG/MgCl2/PEG-g-CDA powders were synthesized at different temperatures via liquid-phase reaction method. The microstructures of the synthesized powders were analyzed and characterized by FT-IR, XRD and ChemDraw software. The effects of synthesized temperatures on infrared emissivity properties of the powders in the wavelength range 3-5 μm were investigated systematically. It is found that the powders heated at 100 °C exhibit the optimum crystallinity at room temperature and thus show the largest variation (0.4) in infrared emissivity with the test temperature varying from 50 °C to 65 °C. Furthermore, the mechanisms for the self-regulated infrared emissivity properties are also explored thoroughly. The variation of infrared emissivity with temperature is ascribed to the changes in resistivity, which is induced by the transformation of PEG-g-CDA between crystalline and amorphous as well as the molecular structure transition of BCG between quinone and lactone. Our results suggest that BCG/MgCl2/PEG-g-CDA powders are potential candidates for intelligent infrared camouflage.