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Size, concentration, and solvency effects on the viscosifying behavior of PEO-PS-PEO triblock copolymers in AOT oil-continuous microemulsions

Lynch, Iseult LU and Piculell, Lennart LU (2004) In The Journal of Physical Chemistry Part B 108(22). p.7515-7522
Abstract
The effect of changing the block lengths of triblock copolymers of poly(ethylene oxide) -polystyrene -poly(ethylene oxide) on the relative viscosity of AOT oil-continuous microemulsions, with cyclohexane as the oil, was investigated. Five different microemulsion compositions were used to have (a) a series of increasing droplet concentration at constant droplet size and (b) a series with increasing droplet size at constant droplet weight fraction. All polymer and microemulsion mixtures showed Newtonian viscosity, and in all cases the presence of a polymer in the microemulsion led to an increase in the viscosity. Results were presented at 40 degreesC, which is above the theta temperature of polystyrene in cyclohexane. With all polymers, the... (More)
The effect of changing the block lengths of triblock copolymers of poly(ethylene oxide) -polystyrene -poly(ethylene oxide) on the relative viscosity of AOT oil-continuous microemulsions, with cyclohexane as the oil, was investigated. Five different microemulsion compositions were used to have (a) a series of increasing droplet concentration at constant droplet size and (b) a series with increasing droplet size at constant droplet weight fraction. All polymer and microemulsion mixtures showed Newtonian viscosity, and in all cases the presence of a polymer in the microemulsion led to an increase in the viscosity. Results were presented at 40 degreesC, which is above the theta temperature of polystyrene in cyclohexane. With all polymers, the relative viscosity decreased with increasing droplet concentration (at constant droplet size) and, in general, increased with increasing droplet size (at constant droplet weight fraction), although there were some exceptions. Comparing the viscosifying behavior of the different triblock copolymers on the molar scale (moles of polymer/dm(3)) resulted in the emergence of trends that are significantly different from those of previous investigations of triblock copolymers in microemulsions. In particular, we show evidence that increasing the PS block length leads to increased viscosity enhancement. However, at high droplet concentration this increased viscosity enhancement with long PS blocks is lost as the system comes closer to the segregative phase-separation boundary. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
The Journal of Physical Chemistry Part B
volume
108
issue
22
pages
7515 - 7522
publisher
The American Chemical Society
external identifiers
  • wos:000221700300082
  • scopus:2942735191
ISSN
1520-5207
DOI
10.1021/jp049147t
language
English
LU publication?
yes
id
ead65132-15f9-4f6c-b954-a645be25e0fe (old id 153931)
date added to LUP
2007-07-11 15:52:33
date last changed
2017-01-01 07:03:22
@article{ead65132-15f9-4f6c-b954-a645be25e0fe,
  abstract     = {The effect of changing the block lengths of triblock copolymers of poly(ethylene oxide) -polystyrene -poly(ethylene oxide) on the relative viscosity of AOT oil-continuous microemulsions, with cyclohexane as the oil, was investigated. Five different microemulsion compositions were used to have (a) a series of increasing droplet concentration at constant droplet size and (b) a series with increasing droplet size at constant droplet weight fraction. All polymer and microemulsion mixtures showed Newtonian viscosity, and in all cases the presence of a polymer in the microemulsion led to an increase in the viscosity. Results were presented at 40 degreesC, which is above the theta temperature of polystyrene in cyclohexane. With all polymers, the relative viscosity decreased with increasing droplet concentration (at constant droplet size) and, in general, increased with increasing droplet size (at constant droplet weight fraction), although there were some exceptions. Comparing the viscosifying behavior of the different triblock copolymers on the molar scale (moles of polymer/dm(3)) resulted in the emergence of trends that are significantly different from those of previous investigations of triblock copolymers in microemulsions. In particular, we show evidence that increasing the PS block length leads to increased viscosity enhancement. However, at high droplet concentration this increased viscosity enhancement with long PS blocks is lost as the system comes closer to the segregative phase-separation boundary.},
  author       = {Lynch, Iseult and Piculell, Lennart},
  issn         = {1520-5207},
  language     = {eng},
  number       = {22},
  pages        = {7515--7522},
  publisher    = {The American Chemical Society},
  series       = {The Journal of Physical Chemistry Part B},
  title        = {Size, concentration, and solvency effects on the viscosifying behavior of PEO-PS-PEO triblock copolymers in AOT oil-continuous microemulsions},
  url          = {http://dx.doi.org/10.1021/jp049147t},
  volume       = {108},
  year         = {2004},
}