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

Title data

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. Vol. 11 (2009) Issue 7 . - pp. 1098-1104.
ISSN 1463-9084
DOI: https://doi.org/10.1039/b814946a

Official URL: Volltext

Abstract in another language

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.

Further data

Item Type: Article in a journal
Refereed: Yes
Institutions of the University: Faculties > Faculty of Biology, Chemistry and Earth Sciences
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Former Professors > Chair Physical Chemistry II - Univ.-Prof. Dr. Andreas Fery
Faculties
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Chair Physical Chemistry II
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Former Professors
Result of work at the UBT: Yes
DDC Subjects: 500 Science > 500 Natural sciences
500 Science > 530 Physics
500 Science > 540 Chemistry
Date Deposited: 08 Dec 2014 09:42
Last Modified: 08 Dec 2014 09:42
URI: https://eref.uni-bayreuth.de/id/eprint/4002