Reconfigurable wrinkled surfaces for dynamic thermal management and infrared camouflage

Abstract

In recent years, materials with dynamically tunable infrared radiation properties have driven advancements in thermal management and infrared camouflage. When the temperature of an object or its surrounding environment significantly varies, a wide range of infrared emissivity modulations is required to provide sufficient infrared radiation regulation capability for practical applications. In this work, we propose a metallic wrinkled surface with widely tunable emissivity. The undulations of surface wrinkles and the proportion of crack areas on a flexible substrate can be reversibly tuned through mechanical stretching and contraction, thereby modulating the reflection, scattering, and transmission of infrared light, achieving dynamic control over the radiation properties. The application of pre-strain during the fabrication process reduced the initial crack coverage on the wrinkled surface, resulting in a lower minimum emissivity value. Under subsequent tensile deformation, the increased crack coverage and the regeneration of wrinkles together elevated the maximum emissivity value. These two effects collectively broadened the overall infrared emissivity modulation range of the wrinkled surface. The designed wrinkled surface is capable of continuously modulating the infrared emissivity within the range of 0.02–0.65 under 120 % uniaxial tensile strain and maintains this modulation range even after 200 stretching cycles. This range satisfies the theoretical requirements for emissivity modulation in both thermal management and infrared camouflage applications, demonstrating its potential for use in dynamic infrared camouflage and thermal management scenarios involving large environmental temperature fluctuations.