Infrared Thermochromic Antennas Composites for Self-Adaptive Thermal Radiators

Passive thermoregulation, the ability of organisms to self-regulate their body temperature, offers significant potential for reducing energy usage in heating and cooling applications. Although engineering thermochromic materials have been explored to achieve this functionality, a technology that integrates large emissivity modulation with scalability, affordability, and versatile end-product designs remains undeveloped. In this work, we introduce infrared thermochromic antennas—non-spherical particles that exhibit a substantial increase (∼150 times) in their absorption cross-section with rising temperatures, and tunable across specific spectral regions. We will discuss the critical design parameters, including the morphology, size distribution, and concentration of the antennas, and establish guidelines for creating materials with large hot/cold emissivity switching (~ 0.9). Additionally, by incorporating these infrared thermochromic antennas into polymer matrices or through direct spraying, we demonstrate an adaptable and cost-efficient method for mass-producing passive thermoregulation paints, fabrics, and films. These materials hold potential for diverse applications, such as self-adaptive radiative cooling, thermal sensing, and thermal camouflage.