Cellulose-based aerogel material with a three-layer gradient structure for both thermal management and infrared camouflage.

Infrared camouflage materials have an important position in the field of national defence and military. However, monofunctional aerogel are unable to adjust their temperature in real time in response to changes in site and ambient temperatures, detected by detectors. Here, a multifunctional cellulose aerogel (MGSCA) with sandwich structure was fabricated by integrating electrothermal conversion layer (cellulose aerogel doped with MXene), thermal insulating layer (silane-modified cellulose aerogel), and thermal infrared camouflage layer (PU mixed with Cu). Based on the electrothermal conversion of MXene, aerogel cavity structure, and radiation energy absorption of Cu, the MGSCA shows excellent comprehensive performance including thermal management and thermal infrared camouflage. It can quickly reach 70.3 °C under 6.5 V and its infrared emissivity can reduce to 0.361. Besides, MGSCA can effectively prevent the temperature transfer between the inside and outside ambient, which is attributed to the low thermal conductivity of intermediate layer (0.0319 W·m·K). Composites using the sandwich structural provide thermal comfort to the target in harsh and cold environments while acquiring thermal camouflage capability. This exploration provides a promising approach to the design of advanced functional materials for thermal management and long-lasting infrared stealth and camouflage.