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Soft X-ray induced modifications of PVA-based microbubbles in aqueous environment : a microspectroscopy study

Titelangaben

Tzvetkov, George ; Fernandes, Paulo A. L. ; Wenzel, Stephan ; Fery, Andreas ; Paradossi, Gaio ; Fink, Rainer H.:
Soft X-ray induced modifications of PVA-based microbubbles in aqueous environment : a microspectroscopy study.
In: Physical Chemistry Chemical Physics. Bd. 11 (2009) Heft 7 . - S. 1098-1104.
ISSN 1463-9084
DOI: https://doi.org/10.1039/b814946a

Volltext

Link zum Volltext (externe URL): Volltext

Abstract

We use scanning-transmission X-ray microspectroscopy (STXM) for in situ characterization of the physicochemical changes in air-filled poly(vinyl alcohol) (PVA) based microbubbles upon soft X-ray irradiation. The microbubbles were illuminated directly in aqueous suspension with 520 eV X-rays and a continuous shrinkage of the particles with an illumination time/radiation dose was observed. Utilizing the intrinsic absorption properties of the species and the high spatial resolution of the STXM, the modifications of the particles' structure were simultaneously recognized. A thorough characterization of the microbubble volume, membrane thickness and absorption coefficient was performed by quantitative fitting of the radial transmittance profiles of the targeted microbubbles. Apart from the observed volume contraction, there was no significant change in the shell thickness. The chemical changes in the membranes were clarified via C K-edge near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. It was revealed that the observed structural alterations go along with a continuous degradation of the PVA network associated with formation of carbonyl-and carboxyl-containing species as well as an increased content of unsaturated bonds.

Weitere Angaben

Publikationsform: Artikel in einer Zeitschrift
Begutachteter Beitrag: Ja
Institutionen der Universität: Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften
Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie
Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie > Ehemalige Professoren > Lehrstuhl Physikalische Chemie II - Univ.-Prof. Dr. Andreas Fery
Fakultäten
Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie > Lehrstuhl Physikalische Chemie II
Fakultäten > Fakultät für Biologie, Chemie und Geowissenschaften > Fachgruppe Chemie > Ehemalige Professoren
Titel an der UBT entstanden: Ja
Themengebiete aus DDC: 500 Naturwissenschaften und Mathematik > 500 Naturwissenschaften
500 Naturwissenschaften und Mathematik > 530 Physik
500 Naturwissenschaften und Mathematik > 540 Chemie
Eingestellt am: 08 Dec 2014 09:42
Letzte Änderung: 08 Dec 2014 09:42
URI: https://eref.uni-bayreuth.de/id/eprint/4002