Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published May 21, 2010 | Published
Journal Article Open

Self-consistent field theory of polymer-ionic molecule complexation

Abstract

A self-consistent field theory is developed for polymers that are capable of binding small ionic molecules (adsorbates). The polymer-ionic molecule association is described by Ising-like binding variables, C_(i)^(a)(kΔ)(= 0 or 1), whose average determines the number of adsorbed molecules, nBI. Polymer gelation can occur through polymer-ionic molecule complexation in our model. For polymer-polymer cross-links through the ionic molecules, three types of solutions for nBI are obtained, depending on the equilibrium constant of single-ion binding. Spinodal lines calculated from the mean-field free energy exhibit closed-loop regions where the homogeneous phase becomes unstable. This phase instability is driven by the excluded-volume interaction due to the single occupancy of ion-binding sites on the polymers. Moreover, sol-gel transitions are examined using a critical degree of conversion. A gel phase is induced when the concentration of adsorbates is increased. At a higher concentration of the adsorbates, however, a re-entrance from a gel phase into a sol phase arises from the correlation between unoccupied and occupied ion-binding sites. The theory is applied to a model system, poly(vinyl alcohol) and borate ion in aqueous solution with sodium chloride. Good agreement between theory and experiment is obtained

Additional Information

© 2010 American Institute of Physics. Received 14 March 2010; accepted 27 April 2010; published online 17 May 2010. We would like to thank Dr. Robert Pelton and Mr. Yuguo Cui for many useful discussions on labile polymers. This work was supported by the Natural Sciences and Engineering Research Council of Canada NSERC.

Attached Files

Published - Nakamura2010p10334J_Chem_Phys.pdf

Files

Nakamura2010p10334J_Chem_Phys.pdf
Files (418.0 kB)
Name Size Download all
md5:e87bfbdd938ecf91cff1bfcbdfbef8b9
418.0 kB Preview Download

Additional details

Created:
August 19, 2023
Modified:
October 20, 2023