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Lookup NU author(s): Professor Mark GeogheganORCiD
This is the authors' accepted manuscript of an article that has been published in its final definitive form by American Institute of Physics Publishing, 2021.
For re-use rights please refer to the publisher's terms and conditions.
Fluorescence correlation spectroscopy was used to show that the temperature-dependent diffusion coefficient of poly(ethylene oxide) (PEO) adsorbed on polystyrene and different poly(alkyl methacrylate) (PAMA) films in aqueous solution exhibited a maximum close to (but below) the surface glass transition temperature, Tgs, of the film. This elevated diffusion was observed over a small range of temperatures below Tgs for these surfaces, and at other temperatures, the diffusion was similar to that on silicon, although the diffusion coefficient for PEO on polystyrene at temperatures above Tgs did not completely decrease to that on silicon, in contrast to the PAMA surfaces. It is concluded that the enhanced surface mobility of the films near the surface glass transition temperature induces conformational changes in the adsorbed PEO. The origin of this narrow and dramatic increase in diffusion coefficient is not clear, but it is proposed that it is caused by a coupling of a dominant capillary mode in the liquid surface layer with the polymer. Friction force microscopy experiments also demonstrate an unexpected increase in friction at the same temperature as the increase in diffusion coefficient
Author(s): Mears M, Zhang ZJ, Jackson RCD, Si Y, Bradford TJB, Torkelson JM, Geoghegan M
Publication type: Article
Publication status: Published
Journal: Journal of Chemical Physics
Year: 2021
Volume: 154
Issue: 16
Print publication date: 28/04/2021
Online publication date: 23/04/2021
Acceptance date: 07/04/2021
Date deposited: 04/08/2021
ISSN (print): 0021-9606
ISSN (electronic): 1089-7690
Publisher: American Institute of Physics Publishing
URL: https://doi.org/10.1063/5.0051351
DOI: 10.1063/5.0051351
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