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Association of a hydrophobically modified polyelectrolyte and a block copolymer followed by fluorescence techniques

Costa, Telma LU ; Schillén, Karin LU ; Miguel, Maria LU ; Lindman, Björn LU and Seixas de Melo, J. Sergio (2009) In The Journal of Physical Chemistry Part B 113(18). p.6194-6204
Abstract
By using absorption and fluorescence (steady-state and time-resolved) techniques the

interaction between a poly(acrylic acid) PAA, randomly grafted with pyrene (Py) units

(PAAMePy55) and a triblock copolymer of poly(ethylene oxide) and poly(propylene

oxide) (EO20PO68EO20, P123) was investigated. From the fluorescence data it is shown

that upon addition of P123 a decrease of the (pyrene-pyrene, Py-Py) intramolecular

association, i.e., a decrease of dynamic and static excimer formation, is observed. Timeresolved

fluorescence data reveal the existence of two types of monomers (monomers

that are able to form excimer, MAGRE, and isolated monomers) and two excimers.

Addition... (More)
By using absorption and fluorescence (steady-state and time-resolved) techniques the

interaction between a poly(acrylic acid) PAA, randomly grafted with pyrene (Py) units

(PAAMePy55) and a triblock copolymer of poly(ethylene oxide) and poly(propylene

oxide) (EO20PO68EO20, P123) was investigated. From the fluorescence data it is shown

that upon addition of P123 a decrease of the (pyrene-pyrene, Py-Py) intramolecular

association, i.e., a decrease of dynamic and static excimer formation, is observed. Timeresolved

fluorescence data reveal the existence of two types of monomers (monomers

that are able to form excimer, MAGRE, and isolated monomers) and two excimers.

Addition of P123 causes also an increase of the amount of isolated Py monomers. The

overall fluorescence data suggest that the PAAMePy55 and the P123 block copolymer

associate strongly at low pH, leading to the formation of P123 micelles surrounded by

one PAAMePy55 chain, where the pyrene groups are located at the PPO/PEO interface

of the P123 micelles. Steady-state fluorescence results also showed that an excess of

P123 micelles in solution is required for the association to occur. At high pH (pH 9 and

above), the situation is less clear, the steady-state (particularly in the I1/I3 ratio) and

time-resolved fluorescence results indicate a contact between the pyrene groups and

PEO, which then would imply that there may be an interaction, but much weaker than at

low pH. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
The Journal of Physical Chemistry Part B
volume
113
issue
18
pages
6194 - 6204
publisher
The American Chemical Society
external identifiers
  • pmid:19354273
  • wos:000265687500004
  • scopus:66349109972
ISSN
1520-5207
DOI
10.1021/jp8093879
language
English
LU publication?
yes
id
bbed9123-0620-4f0c-95f3-9afd85113394 (old id 1291751)
date added to LUP
2009-02-05 15:49:58
date last changed
2017-06-04 04:11:13
@article{bbed9123-0620-4f0c-95f3-9afd85113394,
  abstract     = {By using absorption and fluorescence (steady-state and time-resolved) techniques the<br/><br>
interaction between a poly(acrylic acid) PAA, randomly grafted with pyrene (Py) units<br/><br>
(PAAMePy55) and a triblock copolymer of poly(ethylene oxide) and poly(propylene<br/><br>
oxide) (EO20PO68EO20, P123) was investigated. From the fluorescence data it is shown<br/><br>
that upon addition of P123 a decrease of the (pyrene-pyrene, Py-Py) intramolecular<br/><br>
association, i.e., a decrease of dynamic and static excimer formation, is observed. Timeresolved<br/><br>
fluorescence data reveal the existence of two types of monomers (monomers<br/><br>
that are able to form excimer, MAGRE, and isolated monomers) and two excimers.<br/><br>
Addition of P123 causes also an increase of the amount of isolated Py monomers. The<br/><br>
overall fluorescence data suggest that the PAAMePy55 and the P123 block copolymer<br/><br>
associate strongly at low pH, leading to the formation of P123 micelles surrounded by<br/><br>
one PAAMePy55 chain, where the pyrene groups are located at the PPO/PEO interface<br/><br>
of the P123 micelles. Steady-state fluorescence results also showed that an excess of<br/><br>
P123 micelles in solution is required for the association to occur. At high pH (pH 9 and<br/><br>
above), the situation is less clear, the steady-state (particularly in the I1/I3 ratio) and<br/><br>
time-resolved fluorescence results indicate a contact between the pyrene groups and<br/><br>
PEO, which then would imply that there may be an interaction, but much weaker than at<br/><br>
low pH.},
  author       = {Costa, Telma and Schillén, Karin and Miguel, Maria and Lindman, Björn and Seixas de Melo, J. Sergio},
  issn         = {1520-5207},
  language     = {eng},
  number       = {18},
  pages        = {6194--6204},
  publisher    = {The American Chemical Society},
  series       = {The Journal of Physical Chemistry Part B},
  title        = {Association of a hydrophobically modified polyelectrolyte and a block copolymer followed by fluorescence techniques},
  url          = {http://dx.doi.org/10.1021/jp8093879},
  volume       = {113},
  year         = {2009},
}