Berlin 2012 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 8: Poster: Nanoparticles and Composite Materials
CPP 8.23: Poster
Montag, 26. März 2012, 17:30–20:00, Poster A
Scanning transmission x-ray microscopy and quantitative analysis of thermoresponsive microgels — •Andreas Späth1, Birgit Graf-Zeiler1, Shivkumar Ghugare2, Gaio Paradossi2, and Rainer H. Fink1 — 1Friedrich-Alexander Universität Erlangen-Nürnberg, Physical Chemistry II, Erlangen, Germany — 2Università di Roma Tor Vergata, Scienze e Tecnologie Chimiche, Rome, Italy
Microgels have attracted greater attention in a broad field of medical science. They unify features of macroscopic hydrogels like the connectivity and the responsivity to environmental changes with the colloidal characteristics of nano- or micro-sized systems. To gain deeper insight into the processes occurring during heating above the volume phase transition temperature, we investigate PVA/poly(methacrylate-co-N-isopropylacrylamide) based networks using scanning transmission X-ray microspectroscopy. The PolLux-STXM (SLS) combines local-spot chemical information (NEXAFS) and imaging with a resolution limit below 30 nm. Therefore we recheive new insight into the nanoscale properties of these materials and directly observe the shrinking behaviour of thermoresponsive microgels in aqueous solution in situ [1]. NEXAFS studies confirm the chemical stability of the particles above the volume phase transition temperature [2]. The qualitative analysis of the recheived transmittance profiles bases on the Lambert-Beer expression corrected by the finite width of the focused X-ray beam.
[1] Graf-Zeiler, B., et al., ChemPhysChem, 2011, DOI: 10.1002/cphc.201100370.
[2] Ghugare, S., et al., Macromolecules, 2011, 44 (11), 4470.