A composite film with multimodal thermoregulation and tunable infrared signature for thermal management and dynamic thermal camouflage

The static and single-functional nature of conventional thermal management and camouflage materials severely limits their adaptability to dynamic environmental conditions. Herein, a Janus composite film (P s P n M) integrating multiple thermoregulation methods and tunable infrared signature is reported. The film consists of poly (arylene ether sulfone ketone) (PPESK)/titanium Dioxide (TiO 2 ) layer (P s ), PPESK/n-octadecane layer (P n ), and MXene layer. The Ps side with a micro/nano-porous structure exhibits high solar reflectivity (0.900) and high infrared emissivity (0.954), enabling passive radiative cooling (PRC) that can reduce the temperature by 8.6 °C. The finger-like pore structure within the Pn layer facilitates the adsorption and accommodation of n-octadecane, thus providing the film with a satisfactory thermal storage density (137.6 J g −1 ). This film facilitates reliable all-weather thermal management through the combined effects of passive radiative heating (PRH), solar heating (SH), and active Joule heating. Furthermore, the surface infrared (IR) signature can be precisely tuned through the synergistic modulation of emissivity and temperature, enabling effective thermal camouflage under ambient conditions, elevated temperatures, and sunlight exposure. By flipping the film, dynamic switching between operational modes can be achieved. This study offers new insights into designing multifunctional materials suitable for advanced thermal management and dynamic thermal camouflage in complex environments.