Engineered spectrally selective and spatially segmented emittances for infrared camouflage textiles

Infrared (IR) camouflage conceals objects by reducing their temperatures or thermal emittances within the mid-wave IR (3-5 mu m) and long-wave IR (8-14 mu m) atmospheric transparent windows. Concerning textiles for IR camouflage on human bodies, it is crucial to consider not only low thermal emittances but also factors such as thermal comfort, resistance to abrasion and washing, breathability, and even blending with the intricate IR background. In this study, we develop a spectrally selective emittance textile (SET) using a roll-to-roll (R2R) magnetron sputtering deposition process. The unique properties of the SET arise from asymmetric Fabry-Perot (F-P) cavity and surface impedance matching, resulting in low emittances of 0.39 and 0.44 in the IR detection wavelength range of 3-5 and 8-14 mu m, respectively, and a high emittance of 0.79 in the undetectable range of 5-8 mu m, enhancing thermal comfort. To improve the SET's resistance to abrasion and washing while maintaining breathability, we apply a highly IR-transparent polymer, styrene-ethylene-butylene-styrene (SEBS), to form a honeycomb pattern using a 3D-printed mask, producing a durable spectrally selective emittance textile (D-SET). The SEBS overcoating not only protects the IR camouflage textiles but also offers a versatile means of further engineering thermal emittance, realizing a spatially segmented emittance pattern with various IR colors, and ultimately achieving the IR-colorful spectrally selective emittance textile (IRC-SET). This work presents an approach aimed at achieving IR camouflage in textiles with both spectrally selective and spatially segmented emittances using scalable manufacturing techniques, which shows considerable potential for advancing the production and application of IR camouflage textiles in real-world scenarios. D-SET not only achieves effective IR camouflage but also dissipates human body heat through radiative cooling, ensuring thermal comfort, while maintaining excellent durability and breathability. IRC-SET enables IR camouflage in complex backgrounds.