International Journal

Temperature-Responsive Thermal Metamaterials Enabled by Modular Design of Thermally Tunable Unit Cells
Author
Sunggu Kang, Jonghwan Cha, Kyeongbeom Seo, Sejun Kim, Youngsun Cha, HowonLee, Jingsung Park and Wonjoon Choi*
Journal
International Journal of Mass and Heat Transfer
Vol
130
Page
469
Year
2019
File
2019_Int. J. Heat Mass Transf..pdf (3.5M) 6회 다운로드 DATE : 2022-03-07 11:42:23

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Integrated circuits or miniaturized portable electronics require adaptive thermal control under certain temperatures. Thermal metamaterials (TMs), which artificially manipulate the heat passing through mediums have shown innovative thermal functions at a continuum scale. However, they cannot implement tunable thermal functions at local spots depending on the operating temperatures. Herein, we introduce temperature-responsive TMs enabled by modular design of thermally tunable unit cells. As ambient temperature changes, tunable thermal shifters can dynamically turn on/off their intrinsic functions to guide anisotropic heat transfer through the transition of thermal conductivities from the inner phase change nanocomposites (PCNCs), and their modular design realizes temperature-responsive thermal shields having switchable functions. The layered structures of stainless steel and the PCNC of n-octadecane embedding carbon nanotubes and copper powder are fabricated as tunable thermal shifters. Their 4 × 4 modular structure confirms the feasibility of temperature-responsive TMs, verified by the disappearance and appearance of thermally shielded regimes at low- and high-temperature ranges. The potential use of the developed concept was demonstrated as tunable interfaces between thermal dissipation and insulation for protecting temperature-sensitive components. This work can offer new capabilities for conventional passive TMs, such as local thermal adaptation, active thermal control interface, and thermal disturbance mitigation.