Search for the Origin of Discrepancies in Osmotic Measurements of the PNIPAM - Water System

Major, still unelucidated, inconsistencies exist in the literature among measurements of the thermodynamic properties of poly(N-isopropylacrylamide) (PNIPAM) solutions and gels. This paper looks for evidence of intrinsic ionic behaviour in cross-linked PNIPAM homopolymer hydrogels synthesized in wat...

Teljes leírás

Elmentve itt :
Bibliográfiai részletek
Szerzők: Manek Enikő
Csákiné Tombácz Etelka
Geissler Erik
Nagyné László Krisztina
Dokumentumtípus: Cikk
Megjelent: 2017
Sorozat:PERIODICA POLYTECHNICA-CHEMICAL ENGINEERING 61 No. 1
doi:10.3311/PPch.10273

mtmt:3216918
Online Access:http://publicatio.bibl.u-szeged.hu/18137
Leíró adatok
Tartalmi kivonat:Major, still unelucidated, inconsistencies exist in the literature among measurements of the thermodynamic properties of poly(N-isopropylacrylamide) (PNIPAM) solutions and gels. This paper looks for evidence of intrinsic ionic behaviour in cross-linked PNIPAM homopolymer hydrogels synthesized in water under standard conditions. Systematic measurements are made of the swelling and osmotic properties of lightly cross-linked PNIPAM hydrogels, as well as of their potentiometric titration and DSC response, over a wide range of pH and ionic strength conditions, in order to distinguish the effects of the latter two parameters on putative intrinsic ions. The intrinsic ion content of the gel is found to be vanishingly small, and consequently unlikely to be the source of the divergences among past measurements. By contrast, a major finding of this study is that comparison of the present results with the literature reveals that frustrated equilibrium can be a source of substantial discrepancies.
Terjedelem/Fizikai jellemzők:39-50
ISSN:0324-5853