Mobility gradients yield rubbery surfaces on top of polymer glasses

Zhiwei Hao, Asieh Ghanekarade, Ningtao Zhu, Katelyn Randazzo, Daisuke Kawaguchi, Keiji Tanaka, Xinping Wang, David S. Simmons (), Rodney D. Priestley () and Biao Zuo ()
Additional contact information
Zhiwei Hao: Zhejiang Sci-Tech University
Asieh Ghanekarade: University of South Florida
Ningtao Zhu: Zhejiang Sci-Tech University
Katelyn Randazzo: Princeton University
Daisuke Kawaguchi: Kyushu University
Keiji Tanaka: Kyushu University
Xinping Wang: Zhejiang Sci-Tech University
David S. Simmons: University of South Florida
Rodney D. Priestley: Princeton University
Biao Zuo: Zhejiang Sci-Tech University

Nature, 2021, vol. 596, issue 7872, 372-376

Abstract: Abstract Many emerging materials, such as ultrastable glasses1,2 of interest for phone displays and OLED television screens, owe their properties to a gradient of enhanced mobility at the surface of glass-forming liquids. The discovery of this surface mobility enhancement3–5 has reshaped our understanding of the behaviour of glass formers and of how to fashion them into improved materials. In polymeric glasses, these interfacial modifications are complicated by the existence of a second length scale—the size of the polymer chain—as well as the length scale of the interfacial mobility gradient6–9. Here we present simulations, theory and time-resolved surface nano-creep experiments to reveal that this two-scale nature of glassy polymer surfaces drives the emergence of a transient rubbery, entangled-like surface behaviour even in polymers comprised of short, subentangled chains. We find that this effect emerges from superposed gradients in segmental dynamics and chain conformational statistics. The lifetime of this rubbery behaviour, which will have broad implications in constraining surface relaxations central to applications including tribology, adhesion, and surface healing of polymeric glasses, extends as the material is cooled. The surface layers suffer a general breakdown in time−temperature superposition (TTS), a fundamental tenet of polymer physics and rheology. This finding may require a reevaluation of strategies for the prediction of long-time properties in polymeric glasses with high interfacial areas. We expect that this interfacial transient elastomer effect and TTS breakdown should normally occur in macromolecular systems ranging from nanocomposites to thin films, where interfaces dominate material properties5,10.

Date: 2021
References: Add references at CitEc
Citations: View citations in EconPapers (2)

Downloads: (external link)
https://www.nature.com/articles/s41586-021-03733-7 Abstract (text/html)
Access to the full text of the articles in this series is restricted.

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:nat:nature:v:596:y:2021:i:7872:d:10.1038_s41586-021-03733-7

Ordering information: This journal article can be ordered from
https://www.nature.com/

DOI: 10.1038/s41586-021-03733-7

Access Statistics for this article

Nature is currently edited by Magdalena Skipper

More articles in Nature from Nature
Bibliographic data for series maintained by Sonal Shukla () and Springer Nature Abstracting and Indexing ().