Clustering in polar media
- 25 August 2010
- journal article
- Published by AIP Publishing in The Journal of Chemical Physics
- Vol. 133 (8), 084901
- https://doi.org/10.1063/1.3484235
Abstract
Clustering prevails in water-soluble polymers and biological macromolecules. It has also been observed in polar solvent mixtures. The possible causes of clustering are discussed. A systematic investigation of clustering in poly(ethylene oxide)/d-water solutions has been undertaken using the small-angle neutron scattering method. The poly(ethylene oxide) monomer is formed of an oxygen atom and an ethylene group. Using the random phase approximation, partial Flory–Huggins interaction parameters for the three pairs (oxygen/d-water, ethylene/d-water, and oxygen/ethylene) are derived. Results show that the first two (oxygen/d-water and ethylene/d-water) are characterized by a lower critical solution temperature phase behavior (whereby phase separation occurs upon heating), while the third one (oxygen/ethylene) is characterized by an upper critical solution temperature phase diagram (whereby phase separation occurs upon cooling). It is argued that clustering is caused by the increasing repulsive interaction between oxygen and ethylene for decreasing temperature and increasing polymer volume fraction. This leads to increasing attractive interactions between ethylene groups that stick together.This publication has 12 references indexed in Scilit:
- The mystery of clustering in macromolecular mediaPolymer, 2009
- Comment on “Effective Long-Range Attraction between Protein Molecules in Solution Studied by Small Angle Neutron Scattering”Physical Review Letters, 2006
- Large-Scale Supramolecular Structure in Solutions of Low Molar Mass Compounds and Mixtures of Liquids: I. Light Scattering CharacterizationThe Journal of Physical Chemistry B, 2006
- Unusual phase behavior in mixtures of poly(ethylene oxide) and ethyl alcoholJournal of Polymer Science Part B: Polymer Physics, 2005
- Effective Long-Range Attraction between Protein Molecules in Solutions Studied by Small Angle Neutron ScatteringPhysical Review Letters, 2005
- Insight into Clustering in Poly(ethylene oxide) SolutionsMacromolecules, 2004
- Large-angle X-ray scattering, small-angle neutron scattering, and NMR relaxation studies on mixing states of 1,4-dioxane-water, 1,3-dioxane-water, and tetrahydrofuran-water mixturesJournal of Molecular Liquids, 2003
- Clustering of poly(ethylene oxide) in water revisitedJournal of Polymer Science Part B: Polymer Physics, 2002
- Dilute Aqueous Poly(ethylene oxide) Solutions: Clusters and Single Molecules in Thermodynamic EquilibriumThe Journal of Physical Chemistry, 1996
- Polyethylene oxide does not necessarily aggregate in waterNature, 1990