Skip to main content

Lund University Publications

LUND UNIVERSITY LIBRARIES

Temperature dependent specific ion effects in mixed salt environments on a thermoresponsive poly(oligoethylene glycol methacrylate) brush

Johnson, Edwin C ; Murdoch, Timothy J ; Gresham, Isaac J ; Humphreys, Ben A LU ; Prescott, Stuart W ; Nelson, Andrew ; Webber, Grant B and Wanless, Erica J (2019) In Physical Chemistry Chemical Physics 21(8). p.4650-4662
Abstract
The temperature induced swelling/collapse transition of poly(oligoethylene glycol methacrylate) (POEGMA) brushes has been investigated in electrolyte solutions comprised of multiple anions. The behaviour of a POEGMA brush in mixed salt environments of potassium acetate (KCH3COO, causes collapse) and thiocyanate (KSCN, causes swelling), two ions at opposite ends of the Hofmeister series, has been monitored with neutron reflectometry (NR) and quartz crystal microbalance with dissipation (QCM-D). These techniques revealed that the balance of the swelling/collapse influence of the two ions on the structure of the brush is temperature dependent. At low temperatures in mixed salt environments, the influence of the acetate and... (More)
The temperature induced swelling/collapse transition of poly(oligoethylene glycol methacrylate) (POEGMA) brushes has been investigated in electrolyte solutions comprised of multiple anions. The behaviour of a POEGMA brush in mixed salt environments of potassium acetate (KCH3COO, causes collapse) and thiocyanate (KSCN, causes swelling), two ions at opposite ends of the Hofmeister series, has been monitored with neutron reflectometry (NR) and quartz crystal microbalance with dissipation (QCM-D). These techniques revealed that the balance of the swelling/collapse influence of the two ions on the structure of the brush is temperature dependent. At low temperatures in mixed salt environments, the influence of the acetate and thiocyanate ions appears additive, antagonistic and approximately equal in magnitude, with brush thickness and dissipation similar to the brush in the absence of electrolyte. At higher temperatures, the influence of the acetate ion diminishes, resulting in an increase in the relative influence of the thiocyanate ion on the brush conformation. These temperature dependent specific ion effects are attributed to increased steric crowding in the brush, along with an increased affinity of the thiocyanate ion for the polymer at higher temperatures. (Less)
Please use this url to cite or link to this publication:
author
; ; ; ; ; ; and
publishing date
type
Contribution to journal
publication status
published
subject
in
Physical Chemistry Chemical Physics
volume
21
issue
8
pages
13 pages
publisher
Royal Society of Chemistry
external identifiers
  • scopus:85061861697
ISSN
1463-9084
DOI
10.1039/C8CP06644B
language
English
LU publication?
no
id
352dd7c6-53d8-47bc-9d5c-f6264a41d958
date added to LUP
2022-04-01 21:04:33
date last changed
2022-04-25 02:10:55
@article{352dd7c6-53d8-47bc-9d5c-f6264a41d958,
  abstract     = {{The temperature induced swelling/collapse transition of poly(oligoethylene glycol methacrylate) (POEGMA) brushes has been investigated in electrolyte solutions comprised of multiple anions. The behaviour of a POEGMA brush in mixed salt environments of potassium acetate (KCH<sub>3</sub>COO, causes collapse) and thiocyanate (KSCN, causes swelling), two ions at opposite ends of the Hofmeister series, has been monitored with neutron reflectometry (NR) and quartz crystal microbalance with dissipation (QCM-D). These techniques revealed that the balance of the swelling/collapse influence of the two ions on the structure of the brush is temperature dependent. At low temperatures in mixed salt environments, the influence of the acetate and thiocyanate ions appears additive, antagonistic and approximately equal in magnitude, with brush thickness and dissipation similar to the brush in the absence of electrolyte. At higher temperatures, the influence of the acetate ion diminishes, resulting in an increase in the relative influence of the thiocyanate ion on the brush conformation. These temperature dependent specific ion effects are attributed to increased steric crowding in the brush, along with an increased affinity of the thiocyanate ion for the polymer at higher temperatures.}},
  author       = {{Johnson, Edwin C and Murdoch, Timothy J and Gresham, Isaac J and Humphreys, Ben A and Prescott, Stuart W and Nelson, Andrew and Webber, Grant B and Wanless, Erica J}},
  issn         = {{1463-9084}},
  language     = {{eng}},
  number       = {{8}},
  pages        = {{4650--4662}},
  publisher    = {{Royal Society of Chemistry}},
  series       = {{Physical Chemistry Chemical Physics}},
  title        = {{Temperature dependent specific ion effects in mixed salt environments on a thermoresponsive poly(oligoethylene glycol methacrylate) brush}},
  url          = {{http://dx.doi.org/10.1039/C8CP06644B}},
  doi          = {{10.1039/C8CP06644B}},
  volume       = {{21}},
  year         = {{2019}},
}