Experiments on the Temperature Dependence of Heterogeneous Nucleation on Nanometer-Sized NaCl and Ag Particles

Autor(en)

Siegfried Schobesberger, Paul Winkler, Tamara Pinterich, Aron Vrtala, Markku Kulmala, Paul Wagner

Abstrakt

Experimental investigations on the activation of NaCl and Ag aerosol particles by heterogeneous nucleation of n-propanol vapor at well-defined vapor saturation ratios are presented. Particular emphasis is placed on the temperature dependence of this process from -11 to + 14 degrees C. Aerosols are generated in a tube furnace and electrostatically classified at mean geometric mobility equivalent diameters between 3.6 and 11 nm. Activation probabilities are measured by means of expansion chamber experiments, and onset n-propanol saturation ratios are subsequently determined. The experiments with Ag particles do not produce any unexpected results. The results for NaCl particles, however, show a temperature trend of the onset saturation ratios that is opposite to that predicted by classical nucleation theory. This stresses the important role that surface properties play in heterogeneous nucleation processes. By tentatively assuming a temperature-dependent contact angle, we are able to theoretically reproduce this reversed temperature trend. In addition, the shrinkage of NaCl condensation particles is investigated for varying amounts of n-propanol vapor, and contact angle measurements are performed at temperatures ranging from -7 to + 30 degrees C.

Organisation(en)

Aerosolphysik und Umweltphysik

Externe Organisation(en)

University of Helsinki

Journal

ChemPhysChem: a European journal of chemical physics and physical chemistry

Band

11

Seiten

3874-3882

Anzahl der Seiten

9

ISSN

1439-4235

DOI

https://doi.org/10.1002/cphc.201000417

Publikationsdatum

2010

Peer-reviewed

Ja

ÖFOS 2012

1030 Physik, Astronomie, 105904 Umweltforschung

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/49b345b8-daa1-4c2f-be9e-19952f017158