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Proceedings Paper

Relationship between the volumetric strain and the pH in ionic polymeric gels
Author(s): Mohsen Shahinpoor
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Paper Abstract

A theoretical model is presented for the derivation of a mathematical relationship between the volumetric strain of an ionic polymeric gel and its pH. The model presented also applies to polyelectrolytes in aqueous solutions. The derivation uses an expression for the total electrostatic free energy per single polyelectrolyte molecule which involves a quasi-Debye curvature, the local absolute temperature, the geometric features of polyelectrolyte molecule, the dielectric constant of the gel as well as the local ionic concentrations for the fixed and the mobile charges. The gradient of the free energy with respect to the number of fixed ions is then related to the pH, i.e., the local concentration of hydrogen ions H+, the absolute temperature T and the degree of ionization (alpha) which is defined as the ratio of the number of moles of H+ to the number of moles of the ionizable groups fixed to the ionic gel network. Subsequently, the gradient of the free energy is related to the volumetric strain of the ionic gel network.

Paper Details

Date Published: 23 July 1993
PDF: 8 pages
Proc. SPIE 1916, Smart Structures and Materials 1993: Smart Materials, (23 July 1993); doi: 10.1117/12.148498
Show Author Affiliations
Mohsen Shahinpoor, Univ. of New Mexico (United States)

Published in SPIE Proceedings Vol. 1916:
Smart Structures and Materials 1993: Smart Materials
Vijay K. Varadan, Editor(s)

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