Thermal Interface Hydrogel Composites Mechanically Compliant with Curvy Skins and Rigid Electronic Modules

Abstract The evolution of wearable electronic devices has drawn attention to personal thermal management (PTM) technologies encompassing the sensing and regulation of body temperature and/or harnessing human body heat for energy harvesting. However, solid PTM devices encounter inherent limitations concerning thermal contact and mechanical compatibility with the human body. This study introduces a thermal interface hydrogel exhibiting high thermal conduction and mechanical compatibility with human skin. Employing a strategic design approach, the mechanical and thermal properties of the hydrogel are assessed. This hydrogel is a structured composite incorporating alumina microplatelets embedded layer‐by‐layer within a densified polymer matrix. Incorporating aligned alumina platelets in the layered structure, combined with a densified polymer matrix ensuring close contact and packing of polymer chains, enhances the thermal conductivity of the hydrogel. Simultaneously, it maintains mechanical flexibility and robustness. Subsequently, the resulting hydrogel is showcased as a thermal interface material sandwiched between flexible human skin and a rigid Peltier module for a cooling device affixed to the human skin. Anticipated applications of the hydrogel‐based thermal interface material include advanced bioelectronics with added functionalities in PTM, all without inducing mechanical or physical discomfort.