(210g) Giant Thermal Rectification Efficiency By Asymmetric Thermal Radiation in Polyurethane-Manganese Complex Materials

Functional polymer materials are widely investigated for thermal management including thermal rectification phenomenon. Thermal rectification presents an asymmetric heat transfer wherein thermal conductance varies based on the direction of temperature gradient [1, 2]. Nonlinearity and asymmetry are crucial factors to achieve a high efficiency in thermal rectification. Thermal radiation, as described by the Stefan-Boltzmann law, is a promising mechanism due to its strong nonlinearity with respect to temperature [1, 2]. Here we present a giant thermal rectification efficiency of 218% by dramatically increasing the asymmetry in parameters of the Stefan-Boltzmann law [2]. The asymmetry in emissivity is achieved by sputter-depositing manganese (ε ~ 0.38) on the top right half surface of a polyurethane specimen (ε ~ 0.98). The asymmetry in radiation surface area is achieved by controlling the geometry by the 3D printing technology. The experimentally measured temperature profiles exhibit excellent agreement with the results from finite element analysis, demonstrating reliability. The optimum cost-effective and lightweight designs are investigated by machine learning [2]. This work may find applications in highly efficient scale-up thermal rectification management [2]. The recent advancement in our laboratory will also be introduced. References: [1] Materials Horizons, 2021, 8, 1998–2005 [2] Materials Horizons, 2023, 10, 5720–5728