skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Thermodynamic analysis of hydrogel swelling in aqueous sodium chloride solutions

Journal Article · · Journal of Molecular Liquids
 [1];  [1]
  1. Texas Tech Univ., Lubbock, TX (United States)

Here, a comprehensive thermodynamic model is presented for swelling and salt partitioning of poly (n-isopropyl acrylamide) hydrogels in aqueous sodium chloride (NaCl) solutions at 298 K. Together with a Helmholtz energy expression for network elastic energy, a modified electrolyte Nonradom Two-Liquid activity coefficient model is used to represent both the long-range electrostatic interactions and the short-range van der Waals interactions present in the gel phase. The model parameters include one network parameter per hydrogel system plus two binary parameters per interaction pair in the polymer–solvent-salt systems. With semiquantitave agreement with experimental data for both hydrogel swelling and salt partitioning up to salt saturation, the analysis suggests the ion hydration between NaCl and water is the root cause for hydrogel deswelling in aqueous NaCl solution at high NaCl concentrations, i.e., NaCl weight fraction >0.03. On the other hand, the strong repulsive interaction between NaCl and hydrogel polymer is the dominant factor for salt partitioning.

Research Organization:
American Institute of Chemical Engineers (AIChE), New York, NY (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE)
Grant/Contract Number:
EE0007888
OSTI ID:
1977459
Alternate ID(s):
OSTI ID: 1838557
Journal Information:
Journal of Molecular Liquids, Vol. 348; ISSN 0167-7322
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English

References (20)

Modeling swelling behavior of hydrogels in aqueous organic solvents journal October 2021
Symmetric Electrolyte Nonrandom Two-Liquid Activity Coefficient Model journal August 2009
Thermodynamics of phase equilibrium for systems containing gels journal February 1996
Simple presentation of network theory of rubber, with a discussion of other theories journal April 1949
Poly(vinyl alcohol) hydrogels as soft contact lens material journal January 1994
Swelling of N-isopropyl acrylamide hydrogels in aqueous solutions of sodium chloride journal February 2006
Environment-sensitive hydrogels for drug delivery journal December 2001
Sodium chloride-induced phase transition in nonionic poly(N-isopropylacrylamide) gel journal September 1993
Effects of Salt on the Lower Critical Solution Temperature of Poly ( N -Isopropylacrylamide) journal December 2010
A segment-based local composition model for the gibbs energy of polymer solutions journal February 1993
Swelling of n-isopropyl acrylamide hydrogels in water and aqueous solutions of ethanol and acetone journal May 2004
Modeling Poly( N -isopropylacrylamide) Hydrogels in Water/Alcohol Mixtures with PC-SAFT journal July 2012
Generalized electrolyte-NRTL model for mixed-solvent electrolyte systems journal January 2004
Swelling equilibria for positively ionized polyacrylamide hydrogels journal February 1990
Local composition model for excess Gibbs energy of electrolyte systems. Part I: Single solvent, single completely dissociated electrolyte systems journal July 1982
PNIPAM-MAPOSS Hybrid Hydrogels with Excellent Swelling Behavior and Enhanced Mechanical Performance: Preparation and Drug Release of 5-Fluorouracil journal January 2018
Thermo-Responsive Poly(N-Isopropylacrylamide)-Cellulose Nanocrystals Hybrid Hydrogels for Wound Dressing journal March 2017
Temperature dependence of interaction parameters in electrolyte NRTL model journal November 2015
Thermodynamic representation of the NaCl+Na2SO4+H2O system with electrolyte NRTL model journal July 2011
A local composition model for the excess Gibbs energy of aqueous electrolyte systems journal March 1986