Programmable infrared thermally encodable films with staged energy release for adaptive camouflage and thermal management

Infrared (IR) camouflage materials are essential for next generation stealth and information security technologies, yet most existing approaches, such as surface coating modifications or emissivity tunable thin films, lack programmability, adaptability, or long-term stability. Here, we report a programmable infrared thermally encodable film (ITEF), realized by microfluidic encapsulation of solid-liquid phase change materials (PCMs) into highly uniform microcapsules with precisely engineered core to shell ratios. Each capsule is regarded as a minimal thermal pixel and densely embedded within a flexible polydimethylsiloxane (PDMS) matrix, enabling the thin film to write, erase, and reconfigure infrared patterns in real time. Through a systematic investigation of multiple key parameters including capsule spacing, capsule diameter, core to shell ratio, phase transition temperature of the PCMs, and heating conditions, we demonstrate that the onset time, duration, and complexity of encoded signals can be rationally tailored according to demand. By integrating PCMs with distinct phase transition temperatures, the ITEFs generate both static and sequentially evolving infrared images, thereby achieving dynamic thermal encryption and adaptive camouflage. This study establishes a versatile strategy for tunable and programmable IR materials, transforming individual capsules into functional thermal pixels and opening new opportunities in stealth technologies, thermal encryption, and intelligent thermal management.