High-Strength Polycrystalline Covalent Organic Framework with Abnormal Thermal Transport Insensitive to Grain Boundary,Nano Letters

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High-Strength Polycrystalline Covalent Organic Framework with Abnormal Thermal Transport Insensitive to Grain Boundary
Nano Letters ( IF 9.6 ) Pub Date : 2024-04-01 , DOI: 10.1021/acs.nanolett.4c00570
Weizhe Hao ₁ , Chao Sui ₂ , Gong Cheng ₂ , Junjiao Li ₁ , Yuna Sang ₁ , Chenxi Zhao ₂ , Yichen Zhou ₂ , Zifu Zang ₁ , Yushun Zhao _{1,

2} , Xiaodong He ₂ , Chao Wang _{1,

2}

Affiliation

Grain boundaries (GBs) in two-dimensional (2D) covalent organic frameworks (COFs) unavoidably form during the fabrication process, playing pivotal roles in the physical characteristics of COFs. Herein, molecular dynamics simulations were employed to elucidate the fracture failure and thermal transport mechanisms of polycrystalline COFs (p-COFs). The results revealed that the tilt angle of GBs significantly influences out-of-plane wrinkles and residual stress in monolayer p-COFs. The tensile strength of p-COFs can be enhanced and weakened with the tilt angle, which exhibits an inverse relationship with the defect density. The crack always originates from weaker heptagon rings during uniaxial tension. Notably, the thermal transport in p-COFs is insensitive to the GBs due to the variation of minor polymer chain length at defects, which is abnormal for other 2D crystalline materials. This study contributes insights into the impact of GBs in p-COFs and offers theoretical guidance for structural design and practical applications of advanced COFs.

中文翻译：

对晶界不敏感的异常热传输高强度多晶共价有机骨架

二维 (2D) 共价有机骨架 (COF) 中的晶界 (GB) 在制造过程中不可避免地形成，在 COF 的物理特性中发挥着关键作用。在此，采用分子动力学模拟来阐明多晶COF（p-COF）的断裂失效和热传输机制。结果表明，GBs的倾斜角度显着影响单层p-COFs的面外皱纹和残余应力。 p-COFs的拉伸强度可以随着倾斜角度的增加或减弱而增强或减弱，与缺陷密度呈反比关系。在单轴拉伸过程中，裂纹总是源自较弱的七边形环。值得注意的是，由于缺陷处较小的聚合物链长度的变化，p-COF 中的热传输对 GB 不敏感，这对于其他 2D 结晶材料来说是不正常的。这项研究有助于深入了解GBs对p-COFs的影响，并为先进COFs的结构设计和实际应用提供理论指导。

更新日期：2024-04-01

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