Liang Yuxing, Treaster Kiana A, Majumder Ayan, Settipalli Manoj, Panda Kanishka, Godse Shravan, Roy Rupam, Mali Ratul, Wang Zhongyong, Luan Yuxuan, Hu Peijie, Searles Keith, McLeod David C, Page Kirt A, Bhagwandin Dayanni, Meyhofer Edgar, Reddy Pramod, McGaughey Alan J H, Evans Austin M, Malen Jonathan A
Department of Mechanical Engineering, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, Pennsylvania 15213, United States.
George and Josephine Butler Polymer Research Laboratory, Department of Chemistry, Center for Macromolecular Science and Engineering, University of Florida, Gainesville, Florida 32611, United States.
ACS Nano. 2025 May 27;19(20):19009-19017. doi: 10.1021/acsnano.4c17126. Epub 2025 May 14.
Anisotropic thermal transport was measured in imine-linked two-dimensional polymer (2DP) films that were prepared by interfacial polymerization. Measurements of both in-plane () and cross-plane () thermal conductivities relied on preparing free-standing 2DP films that were readily transferred for different measurement configurations. We polymerized two 2DP (Per-PDA and TAPPy-PDA) films at a liquid-liquid interface. These polycrystalline, imine-linked 2DP films are 100-200 nm in thickness and were measured by frequency domain thermoreflectance to extract and a suspended calorimetric platform technique to evaluate . We find that is larger than in both materials at room temperature, leading to anisotropy ratios (/) as high as 2.3. We attribute this behavior to the fact that the stiff, in-plane covalent bonds of 2DPs transport heat more effectively than the flexible, supramolecular cross-plane interactions. Variable-temperature measurements revealed a positive correlation between temperature and thermal conductivity, which we attribute to phonon scattering from grain boundaries and defects in the polycrystalline 2DP films. Molecular dynamics simulations of pristine crystals predict larger thermal conductivities and anisotropy ratios exceeding 7. The simulations suggest that as higher quality 2DP films become available, higher thermal conductivities and anisotropy ratios will also manifest.
在通过界面聚合制备的亚胺连接二维聚合物（2DP）薄膜中测量了各向异性热传输。面内（）和跨平面（）热导率的测量依赖于制备易于转移以用于不同测量配置的独立2DP薄膜。我们在液-液界面处聚合了两种2DP（Per-PDA和TAPPy-PDA）薄膜。这些多晶的、亚胺连接的2DP薄膜厚度为100 - 200 nm，并通过频域热反射法测量以提取，以及使用悬浮量热平台技术来评估。我们发现，在室温下两种材料中的均大于，导致各向异性比（/）高达2.3。我们将这种行为归因于2DP的刚性面内共价键比柔性超分子跨平面相互作用更有效地传输热量这一事实。变温测量揭示了温度与热导率之间的正相关，我们将其归因于多晶2DP薄膜中晶界和声子散射造成的缺陷。原始晶体的分子动力学模拟预测热导率更大且各向异性比超过7。模拟表明，随着可获得更高质量的2DP薄膜，也将表现出更高的热导率和各向异性比。
