Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

The Mystery of Clustering in Macromolecular Media

Published

Author(s)

Boualem Hammouda

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 (SANS) method. The PEO monomer is formed of an oxygen atom and an ethylene group. Using the Random Phase Approximation (RPA), 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 (LCST) phase behavior (whereby phase separation occurs upon heating), while the third one (oxygen/ethylene) is characterized by an upper critical solution temperature (UCST) phase diagram (whereby phase separation occurs upon cooling). Clustering is caused by the tendency of this last pair (oxygen/ethylene) to demix while the polymer itself dissolves well.
Citation
Polymer
Volume
50

Citation

Hammouda, B. (2010), The Mystery of Clustering in Macromolecular Media, Polymer, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=905298 (Accessed December 11, 2024)

Issues

If you have any questions about this publication or are having problems accessing it, please contact reflib@nist.gov.

Created June 1, 2010, Updated February 19, 2017