The importance of localized modes spectral contribution to thermal conductivity in amorphous polymers
Name
s42005-022-01103-x.pdf
Description
Published version
Size
1.13 MB
Format
Adobe PDF
Checksum (MD5)
4488d9d9cb5bed0f7639839f7b05ec46
Author(s)
Li, Buxuan
DeAngelis, Freddy
Chen, Gang
Henry, Asegun
Date Issued
2022
Journal
Communications Physics
Publisher
Springer Science and Business Media LLC
Citation
Li, Buxuan, DeAngelis, Freddy, Chen, Gang and Henry, Asegun. 2022. "The importance of localized modes spectral contribution to thermal conductivity in amorphous polymers." Communications Physics, 5 (1).
Version
Final published version
Abstract
AbstractPolymers are a unique class of materials from the perspective of normal mode analysis. Polymers consist of individual chains with repeating units and strong intra-chain covalent bonds, and amorphous arrangements among chains with weak inter-chain van der Waals and for some polymers also electrostatic interactions. Intuitively, this strong heterogeneity in bond strength can give rise to special features in the constituent phonons, but such effects have not been studied deeply before. Here, we use lattice dynamics and molecular dynamics to perform modal analysis of the thermal conductivity in amorphous polymers. We find an abnormally large population of localized modes in amorphous polymers, which is fundamentally different from amorphous inorganic materials. Contrary to the common picture of thermal transport, localized modes in amorphous polymers are found to be the dominant contributors to thermal conductivity. We find that a significant portion of the localization happens within individual chains, but heat is dominantly conducted when localized modes involve two chains. These results suggest localized modes generally play a key role in thermal transport for different polymers. The results provide an alternative perspective on why polymer thermal conductivity is generally quite low and gives insight into how to potentially change it.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
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Creative Commons Attribution
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1038/S42005-022-01103-X
