论文标题
使用第一原理的联合原子力场预测的对齐聚乙二醇的高热电导率极高
Extremely High Thermal Conductivity of Aligned Polyacetylene Predicted using First-Principles-Informed United-Atom Force Field
论文作者
论文摘要
聚合物的分子模拟依赖于准确的力场来描述原子间相互作用。在这项工作中，我们使用第一原理密度功能理论（DFT）计算来对聚乙二醇（PA）的联合原子力场进行参数化，这是一种潜在的高热导率的共轭聚合物。 DFT中的不同电子相关函数已经测试。明确描述了共轭聚合物主链中交替的单键和双键的键相互作用，并且分别对II类Anharmonic函数进行了参数化。键角和二面体相互作用也是Anharmonic的，并且针对DFT能量表面进行了参数化。然后，将建立的力场用于分子动力学（MD）模拟，以计算具有不同模拟域长度的单个PA链和PA晶体的导热率。发现PA单链和晶体的热导率值都非常高，并且长度依赖性。在790 nm时，它们的热导率值分别为〜480 wm-1k-1和〜320 wm-1k-1，相对较高比聚乙烯（PE）的高度高，这是最新的最热电学聚合物纤维的最新测量。
Molecular simulations of polymer rely on accurate force fields to describe the inter-atomic interactions. In this work, we use first-principles density functional theory (DFT) calculations to parameterize a united-atom force field for polyacetylene (PA), a conjugated polymer potentially of high thermal conductivity. Different electron correlation functionals in DFT have been tested. Bonding interactions for the alternating single and double bonds in the conjugated polymer backbone are explicitly described and Class II anharmonic functions are separately parameterized. Bond angle and dihedral interactions are also anharmonic and parameterized against DFT energy surfaces. The established force field is then used in molecular dynamics (MD) simulations to calculate the thermal conductivity of single PA chains and PA crystals with different simulation domain lengths. It is found that the thermal conductivity values of both PA single chains and crystals are very high and are length-dependent. At 790 nm, their respective thermal conductivity values are ~480 Wm-1K-1 and ~320 Wm-1K-1, which are comparatively higher than those of polyethylene (PE), the most thermally conductive polymer fiber measured up-to-date.
