Hannover 2010 – wissenschaftliches Programm
UP 2.12: Poster
Dienstag, 9. März 2010, 16:30–18:30, Lichthof
Crystal structures and microcrystal distributions resulting from efflorescence of ternary aerosols — •Lennart Treuel, Alice Sandmann, and Reinhard Zellner — Universität Duisburg-Essen, Essen, Germany
The behaviour of aerosols towards changes in the ambient RH is normally described by their deliquescence and efflorescence. It is established that the addition of organic components may change the deliquescence relative humidity (DRH) of internally mixed salt/organic/water aerosols relative to the pure salt. The deliquescence of complex atmospheric aerosols will inevitably depend on the crystal structures of the effloresced components present in the aerosol. Since the efflorescence process leads to a kinetically controlled crystallisation from highly supersaturated solutions the resulting crystal structures differ greatly from the crystals formed under thermodynamically controlled conditions and hence they may show very different thermodynamic properties. Scanning electron microscopy and the X-ray diffractometry, were used for investigations of crystal structures resulting from the kinetically controlled crystallisation (efflorescence) of highly supersaturated binary and ternary solution droplets. Moreover, scanning Raman microscopy was used to determine the spatial distribution of crystals formed during the efflorescence process within the aerosol particle. The results show a very diverse behaviour of organic and inorganic components, a finding that presents fundamentally new challenges to the pursuit of understanding the very basic principles governing the phase behaviour of complex solutions.