Vo Phuong, Haranczyk Maciej
IMDEA Materials Institute, C/Eric Kandel, 2, 28906 Getafe, Madrid ,Spain.
ACS Appl Mater Interfaces. 2024 Oct 16;16(41):56221-56231. doi: 10.1021/acsami.4c08522. Epub 2024 Oct 3.
Understanding the thermal conductivity in metal-organic framework (MOF)-polymer composites is crucial for optimizing their performance in applications involving heat transfer. In this work, several UiO66-polymer composites (where the polymer is either PEG, PVDF, PS, PIM-1, PP, or PMMA) are examined using molecular simulations. Our contribution highlights the interface's impact on thermal conductivity, observing an overall increasing trend attributable to the synergistic effect of MOF enhancing polymer thermal conductivity. Flexible polymers such as PEG and PVDF exhibit increased compatibility with the MOF, facilitating their integration with the MOF lattice. However, this integration leads to a moderated enhancement in thermal conductivity compared to polymers that remain separate from the MOF structure, such as PS or PP. This effect can be attributed to alterations in phonon transport pathways and shifts in interfacial interactions between the polymer and MOF. Specifically, the infiltration of the polymer like PEG and PVDF into the MOF disrupted the MOF's ordered network, introducing defects or barriers that hindered phonon propagation. In contrast, nonpolar and rigid polymers like PP, PMMA, PS, and PIM-1 exhibited greater improvements in thermal conductivity when combined with MOFs compared to the flexible polymers PVDF and PEG. Most notably, our analysis identifies a critical interface region within approximately 30-50 Å that profoundly influences thermal conductivity. The interface region, as indicated by the density profile and radius of gyration, is notably shorter but plays a pivotal role in modulating the thermal properties. The sensitivity of the system to these interface characteristics underscores the crucial role of this particular interface area in dictating the thermal conductivity. Our findings emphasize the sensitivity of thermal conductivity in polymer matrices to interface characteristics and highlight the critical role of a specific interface region in modulating thermal properties.
了解金属有机框架（MOF）-聚合物复合材料的热导率对于优化其在涉及热传递的应用中的性能至关重要。在这项工作中，使用分子模拟研究了几种UiO66-聚合物复合材料（其中聚合物为PEG、PVDF、PS、PIM-1、PP或PMMA）。我们的研究突出了界面对热导率的影响，观察到由于MOF增强聚合物热导率的协同效应而呈现出总体上升趋势。诸如PEG和PVDF之类的柔性聚合物与MOF表现出更高的相容性，有利于它们与MOF晶格的整合。然而，与诸如PS或PP等与MOF结构保持分离的聚合物相比，这种整合导致热导率的提升较为适度。这种效应可归因于声子传输路径的改变以及聚合物与MOF之间界面相互作用的变化。具体而言，像PEG和PVDF这样的聚合物渗透到MOF中破坏了MOF的有序网络，引入了阻碍声子传播的缺陷或障碍。相比之下，与柔性聚合物PVDF和PEG相比，PP、PMMA、PS和PIM-1等非极性刚性聚合物与MOF结合时热导率有更大的提高。最值得注意的是，我们的分析确定了一个大约30 - 50 Å内的关键界面区域，该区域对热导率有深远影响。如密度分布和回转半径所示，界面区域明显更短，但在调节热性能方面起着关键作用。系统对这些界面特性的敏感性强调了这个特定界面区域在决定热导率方面的关键作用。我们的研究结果强调了聚合物基体中热导率对界面特性的敏感性，并突出了特定界面区域在调节热性能方面的关键作用。
