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

Manek, Enikő and Tombácz, Etelka and Geissler, Erik and László, Krisztina (2017) Search for the Origin of Discrepancies in Osmotic Measurements of the PNIPAM - Water System. PERIODICA POLYTECHNICA-CHEMICAL ENGINEERING, 61 (1). pp. 39-50. ISSN 0324-5853 (print); 1587-3765 (online)

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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.

Item Type: Article
Additional Information: Második szerző: Csákiné Tombácz Etelka Negyedik szerző: Nagyné László Krisztina
Uncontrolled Keywords: PNIPAM, osmotic pressure, DSC, ionic strength, pH
Subjects: T Technology / alkalmazott, műszaki tudományok > TD Environmental technology. Sanitary engineering / környezetvédelem, hulladékkezelés, egészségügyi mérnöki technika (ivóvízellátási és szennyvízkezelési technika)
T Technology / alkalmazott, műszaki tudományok > TP Chemical technology / vegyipar, vegyészeti technológia
Depositing User: MTMT SWORD
Date Deposited: 25 Jun 2019 07:54
Last Modified: 25 Jun 2019 07:54

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