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Temperature and concentration effects on supramolecular aggregation and phase behavior for poly(propylene oxide)-b-poly(ethylene oxide)-b-poly(propylene oxide) copolymers of different composition in aqueous mixtures, 1

D'Errico, G; Paduano, L and Khan, Ali LU (2004) In Journal of Colloid and Interface Science 279(2). p.379-390
Abstract
The phase behavior (temperature vs composition) and microstructure for the two binary systems Pluronic 25R4 [(PO)(19)(EO)33(PO)(19)]-water and Pluronic 25R2 [PO)(21)(EO)(14)(PO)(21)]-water have been studied by a combined experimental approach in the whole concentration range and from 5 to 80 degreesC. The general phase behavior has been identified by inspection under polarized light. Precise phase boundaries have been determined by analyzing H-2 NMR line shape. The identification and microstructural characterization of the liquid crystalline phases have been achieved using small-angle X-ray scattering (SAXS). The isotropic liquid Solution phases have been investigated by self-diffusion measurements (PGSE-NMR method). 25R2 does not form... (More)
The phase behavior (temperature vs composition) and microstructure for the two binary systems Pluronic 25R4 [(PO)(19)(EO)33(PO)(19)]-water and Pluronic 25R2 [PO)(21)(EO)(14)(PO)(21)]-water have been studied by a combined experimental approach in the whole concentration range and from 5 to 80 degreesC. The general phase behavior has been identified by inspection under polarized light. Precise phase boundaries have been determined by analyzing H-2 NMR line shape. The identification and microstructural characterization of the liquid crystalline phases have been achieved using small-angle X-ray scattering (SAXS). The isotropic liquid Solution phases have been investigated by self-diffusion measurements (PGSE-NMR method). 25R2 does not form liquid crystals and is miscible with water in the whole concentration range; with increasing temperature, the mixtures split into water-rich and a copolymer-rich solutions in equilibrium. 25R4 shows rich phase behavior, passing. with increasing copolymer concentration, from a water-rich solution to a lamellar and copolymer-rich solution. A small hexagonal phase, completely encircled in the stability region of the water-rich solution, is also present. In water-rich solutions, at low temperatures and low copolymer concentrations, the copolymers are dissolved as independent macromolecules. With increasing copolymer concentrations an interconnected network of micelles is formed in which micellar cores of hydrophobic poly(propylene oxide) are interconnected by poly(ethylene oxide) strands. In copolymer-rich solutions water is molecularly dissolved in the copolymer. The factors influencing the self-aggregation of Pluronic R copolymers (PPO-PEO-PPO sequence) are discussed, and their behavior in water is compared to that of Pluronic copolymers (PEO-PPO-PEO sequence). (C) 2004 Elsevier Inc. All rights reserved. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Colloid and Interface Science
volume
279
issue
2
pages
379 - 390
publisher
Elsevier
external identifiers
  • pmid:15464802
  • wos:000224929500011
  • scopus:5344242462
ISSN
1095-7103
DOI
10.1016/j.jcis.2004.06.063
language
English
LU publication?
yes
id
f65f6e67-edd7-4944-86d9-9417f47b56fd (old id 154040)
date added to LUP
2007-07-11 09:24:07
date last changed
2017-10-01 03:52:17
@article{f65f6e67-edd7-4944-86d9-9417f47b56fd,
  abstract     = {The phase behavior (temperature vs composition) and microstructure for the two binary systems Pluronic 25R4 [(PO)(19)(EO)33(PO)(19)]-water and Pluronic 25R2 [PO)(21)(EO)(14)(PO)(21)]-water have been studied by a combined experimental approach in the whole concentration range and from 5 to 80 degreesC. The general phase behavior has been identified by inspection under polarized light. Precise phase boundaries have been determined by analyzing H-2 NMR line shape. The identification and microstructural characterization of the liquid crystalline phases have been achieved using small-angle X-ray scattering (SAXS). The isotropic liquid Solution phases have been investigated by self-diffusion measurements (PGSE-NMR method). 25R2 does not form liquid crystals and is miscible with water in the whole concentration range; with increasing temperature, the mixtures split into water-rich and a copolymer-rich solutions in equilibrium. 25R4 shows rich phase behavior, passing. with increasing copolymer concentration, from a water-rich solution to a lamellar and copolymer-rich solution. A small hexagonal phase, completely encircled in the stability region of the water-rich solution, is also present. In water-rich solutions, at low temperatures and low copolymer concentrations, the copolymers are dissolved as independent macromolecules. With increasing copolymer concentrations an interconnected network of micelles is formed in which micellar cores of hydrophobic poly(propylene oxide) are interconnected by poly(ethylene oxide) strands. In copolymer-rich solutions water is molecularly dissolved in the copolymer. The factors influencing the self-aggregation of Pluronic R copolymers (PPO-PEO-PPO sequence) are discussed, and their behavior in water is compared to that of Pluronic copolymers (PEO-PPO-PEO sequence). (C) 2004 Elsevier Inc. All rights reserved.},
  author       = {D'Errico, G and Paduano, L and Khan, Ali},
  issn         = {1095-7103},
  language     = {eng},
  number       = {2},
  pages        = {379--390},
  publisher    = {Elsevier},
  series       = {Journal of Colloid and Interface Science},
  title        = {Temperature and concentration effects on supramolecular aggregation and phase behavior for poly(propylene oxide)-b-poly(ethylene oxide)-b-poly(propylene oxide) copolymers of different composition in aqueous mixtures, 1},
  url          = {http://dx.doi.org/10.1016/j.jcis.2004.06.063},
  volume       = {279},
  year         = {2004},
}