Baker, DL orcid.org/0000-0002-5145-3320, Reynolds, M, Masurel, R et al. (2 more authors) (2022) Cooperative Intramolecular Dynamics Control the Chain-Length-Dependent Glass Transition in Polymers. Physical Review X, 12 (2). 021047. ISSN 2160-3308
Abstract
The glass transition is a long-standing unsolved problem in materials science. For polymers, our understanding of glass formation is particularly poor because of the added complexity of chain connectivity and flexibility; structural relaxation of polymers thus involves a complex interplay between intramolecular and intermolecular cooperativity. Here, we study how the glass-transition temperature Tg varies with molecular weight M for different polymer chemistries and chain flexibilities. We find that Tg(M) is controlled by the average mass (or volume) per conformational degree of freedom and that a “local” molecular relaxation (involving a few conformers) controls the larger-scale cooperative α relaxation responsible for Tg. We propose that dynamic facilitation where a local relaxation facilitates adjacent relaxations, leading to hierarchical dynamics, can explain our observations, including logarithmic Tg(M) dependences. Our study provides a new understanding of molecular relaxations and the glass transition in polymers, which paves the way for predictive design of polymers based on monomer-scale metrics.
Metadata
Authors/Creators: |
|
||||
---|---|---|---|---|---|
Copyright, Publisher and Additional Information: | This item is protected by copyright. This is an open access article under the terms of the Creative Commons Attribution 4.0 International License (CC BY 4.0) (https://creativecommons.org/licenses/by/4.0/) | ||||
Dates: |
|
||||
Institution: | The University of Leeds | ||||
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Physics and Astronomy (Leeds) > Soft Matter Physics (Leeds) | ||||
Funding Information: |
|
||||
Depositing User: | Symplectic Publications | ||||
Date Deposited: | 31 May 2022 09:15 | ||||
Last Modified: | 31 May 2022 09:15 | ||||
Status: | Published | ||||
Publisher: | American Physical Society | ||||
Identification Number: | https://doi.org/10.1103/physrevx.12.021047 | ||||
Related URLs: |