Original scientific paper

Electron Spin Resonance Study of Water Finely Dispersed in Perfluorinated Polymers and of Their Micellar Solutions

Giacomo Martini ; Department of Chemistry, University of Florence, Via G. Capponi 9, 50121 Firenze, Italy
M. Francesca Ottaviani ; Department of Chemistry, University of Florence, Via G. Capponi 9, 50121 Firenze, Italy
Sandra Ristori ; Department of Chemistry, University of Florence, Via G. Capponi 9, 50121 Firenze, Italy

Abstract

The electron spin resonance (ESR) spectroscopy of paramagentic probes (transition metal ions and nitroxide radicals) has been used for the characterization of some properties of perfluorinated compounds. This overview reports on the results obtained in the study of: a) the rheological properties of water finely dispersed into the porosities of the Nafion ionomer and of per- fluoropolyethers (PFPE); in this investigation, neutral and charged small nitroxides were used, whose magnetic parameters and ESR lineshapes are extremely sensitive to the changes of local environments; with V02+ as a probe, both dispersion and aggregation properties of the metal ion into Nafion skeleton have been analyzed; b) the aggregational properties of PFPE in water solution in the form of spherical and non-spherical micelles; large cationic and neutral nitroxides capable of interacting with the molecular assemblies or being trapped in their network allowed us to establish the optimum conditions for the use of spin probes for dynamic and structural studies in these systems and the limits of reliability of the ESR technique in micellar systems.

Keywords

Hrčak ID:

137190

URI

https://hrcak.srce.hr/137190

Publication date:

15.8.1992.

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