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Mixed systems of hydrophobically modified polyelectrolytes: Controlling rheology by charge and hydrophobe stoichiometry and interaction strength

Antunes, Filipe LU ; Lindman, Björn LU and Miguel, Maria LU (2005) In Langmuir 21(22). p.10188-10196
Abstract
Rheology and phase separation were investigated for aqueous mixtures of two oppositely charged hydrophobically modified polyelectrolytes. The typical phase separation, normally seen for oppositely charged polymer mixtures, is dramatically reduced by the presence of hydrophobic modification, and phase separation is only detected close to the point of charge neutralization. While the two polyelectrolytes separately can give high viscosities and a gel-like behavior, a pronounced maximum in viscosity and storage modulus with the mixing ratio of the polyelectrolytes is observed; the maximum is located between the points of charge and hydrophobe stoichiometry and reflects a combination of hydrophobic and electrostatic association. Lowering the... (More)
Rheology and phase separation were investigated for aqueous mixtures of two oppositely charged hydrophobically modified polyelectrolytes. The typical phase separation, normally seen for oppositely charged polymer mixtures, is dramatically reduced by the presence of hydrophobic modification, and phase separation is only detected close to the point of charge neutralization. While the two polyelectrolytes separately can give high viscosities and a gel-like behavior, a pronounced maximum in viscosity and storage modulus with the mixing ratio of the polyelectrolytes is observed; the maximum is located between the points of charge and hydrophobe stoichiometry and reflects a combination of hydrophobic and electrostatic association. Lowering the charge density of the anionic polymer leads to a strengthened association at first, but at lower charge densities there is a weakened association due to the onset of phase separation. The strength of the electrostatic interaction was modified by adding salt. Increased ionic strength can lead to phase separation and to increased or decreased viscosity depending on the polyelectrolyte mixing ratio. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Langmuir
volume
21
issue
22
pages
10188 - 10196
publisher
The American Chemical Society
external identifiers
  • wos:000232731700052
  • scopus:27544506504
ISSN
0743-7463
DOI
10.1021/la050590k
language
English
LU publication?
yes
id
6045997d-d354-4dde-982f-dfc57cd98b18 (old id 157176)
date added to LUP
2007-07-10 16:48:08
date last changed
2017-01-01 04:54:18
@article{6045997d-d354-4dde-982f-dfc57cd98b18,
  abstract     = {Rheology and phase separation were investigated for aqueous mixtures of two oppositely charged hydrophobically modified polyelectrolytes. The typical phase separation, normally seen for oppositely charged polymer mixtures, is dramatically reduced by the presence of hydrophobic modification, and phase separation is only detected close to the point of charge neutralization. While the two polyelectrolytes separately can give high viscosities and a gel-like behavior, a pronounced maximum in viscosity and storage modulus with the mixing ratio of the polyelectrolytes is observed; the maximum is located between the points of charge and hydrophobe stoichiometry and reflects a combination of hydrophobic and electrostatic association. Lowering the charge density of the anionic polymer leads to a strengthened association at first, but at lower charge densities there is a weakened association due to the onset of phase separation. The strength of the electrostatic interaction was modified by adding salt. Increased ionic strength can lead to phase separation and to increased or decreased viscosity depending on the polyelectrolyte mixing ratio.},
  author       = {Antunes, Filipe and Lindman, Björn and Miguel, Maria},
  issn         = {0743-7463},
  language     = {eng},
  number       = {22},
  pages        = {10188--10196},
  publisher    = {The American Chemical Society},
  series       = {Langmuir},
  title        = {Mixed systems of hydrophobically modified polyelectrolytes: Controlling rheology by charge and hydrophobe stoichiometry and interaction strength},
  url          = {http://dx.doi.org/10.1021/la050590k},
  volume       = {21},
  year         = {2005},
}