ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-11-6549-2011 Model HULIS compounds in nanoaerosol clusters – investigations of surface tension and aggregate formation using molecular dynamics simulations Hede T. 1 Li X. 2 3 Leck C. 1 Tu Y. 2 Ågren H. 2 Department of Meteorology, Stockholm University, 10691 Stockholm, Sweden Department of Theoretical Chemistry, School of Biotechnology, Royal Institute of Technology, 10691 Stockholm, Sweden Laboratory for Advanced Materials and Institute of Fine Chemicals, East China University of Science and Technology, Shanghai 200237, China 08 07 2011 11 13 6549 6557 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/11/6549/2011/acp-11-6549-2011.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/11/6549/2011/acp-11-6549-2011.pdf

Cloud condensation nuclei act as cores for water vapour condensation, and their composition and chemical properties may enhance or depress the ability for droplet growth. In this study we use molecular dynamics simulations to show that model humic-like substances (HULIS) in systems containing 10 000 water molecules mimic experimental data well referring to reduction of surface tension. The model HULIS compounds investigated in this study are cis-pinonic acid (CPA), pinic acid (PAD) and pinonaldehyde (PAL). The structural properties examined show the ability for the model HULIS compounds to aggregate inside the nanoaerosol clusters.

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