Volume-phase transitions of ionized N -isopropylacrylamide gels

Equilibrium swelling curves of N-isopropylacrylamide (NIPA) gel and a series of its ionized counterparts were measured as a function of temperature. Nonionic NIPA gels underwent a sharp yet continuous volume change, whereas incorporation of a small amount of ionizable groups into the gel network dri...

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Bibliographic Details
Published inThe Journal of chemical physics Vol. 87; no. 2; pp. 1392 - 1395
Main Authors Hirotsu, Shunsuke, Hirokawa, Yoshitsugu, Tanaka, Toyoichi
Format Journal Article
LanguageEnglish
Published Woodbury, NY American Institute of Physics 15.07.1987
Subjects
Applied sciences
Exact sciences and technology
Organic polymers
Physicochemistry of polymers
Properties and characterization
Solution and gel properties
Solvent effect
Colloidal gel
Temperature
Swelling
Phase transitions
Acrylamide derivative polymer
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Summary:Equilibrium swelling curves of N-isopropylacrylamide (NIPA) gel and a series of its ionized counterparts were measured as a function of temperature. Nonionic NIPA gels underwent a sharp yet continuous volume change, whereas incorporation of a small amount of ionizable groups into the gel network drives the transition toward a discontinuous one. The critical ionic concentration and polymer network density at which the get undergoes a critical phase transition were determined. The results were analyzed using a mean field theory. Discrepancy between experimental data and theory is nontrivial, and may require the formulation of a more elaborate theory.
ISSN:0021-9606
1089-7690
DOI:10.1063/1.453267