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Surface properties of atmospheric aerosol particles are crucial for accurate assessments of the fates of liquid particles in the atmosphere. Surface tension directly influences predictions of particle activation to clouds, as well as indirectly acting as a proxy for chemical surface partitioning. Challenges to accounting for surface effects arise from surface tension dependence on solution concentration and the presence of complex aqueous mixtures in aerosols, includiphyng both surface-active organic solutes and inorganic electrolytes. Also, the interface itself is varied, in that it may be a liquid-vapor interface, as in the surface of an aerosol particle with ambient air, or a liquid-liquid interface between two immiscible liquids, as in the interior surfaces that exist in multiphase particles. In this Feature Article, we highlight our previous work entailing thermodynamic modeling of liquid-vapor surfaces to predict surface tension and microscopic examinations of liquid-liquid interfacial phenomena to measure interfacial tension using biphasic microscale flows. New results are presented for binary aqueous organic acids and their ternary solutions with ammonium sulfate. Ultimately, improved understanding of aerosol particle surfaces would enhance treatment of aerosol particle-to-cloud activation states and aerosol effects on climate.
Bibliographical noteFunding Information:
This material is based upon work supported by the National Science Foundation under Grant No. 1554936. We gratefully acknowledge Prof. Gordon Christopher for sharing microfluidic device design files to aid in the startup of the tensiometry work and Prof. Kevin Dorfman for allowing use of his laboratory and equipment for fabrication of the PDMS microfluidic devices. We also thank and acknowledge our previous coauthors: Dr. Andrew Metcalf for microfluidic interfacial tension measurements; Prof. Anthony Wexler for the genesis of the surface tension model; and Prof. Jonathan P. Reid and Dr. Bryan R. Bzdek at the University of Bristol for their optical tweezers data, whose work was supported by the Engineering and Physical Sciences Research Council 490 (EPSRC) through Grant EP/ L010569/1. Donald Hall is acknowledged for some of the optical tweezers measurements of supersaturated sodium chloride surface tension. Graphic designer Kiley Schmidt is acknowledge for the table of contents and cover art. Part of this work was carried out in the College of Science and Engineering Minnesota Nano Center, University of Minnesota, which receives partial support from NSF through the NNIN program. Part of this work was also carried out in the College of Science and Engineering Coating Process and Visualization Laboratory and the Polymer Characterization Facility, University of Minnesota, which have received capital equipment funding from the NSF through the UMN MRSEC under Award DMR- 1420013. The authors acknowledge funding support for H.C.B. through a National Science Foundation Graduate Research Fellowship through NSF Grant No. 00039202.
© 2017 American Chemical Society.
Copyright 2017 Elsevier B.V., All rights reserved.
How much support was provided by MRSEC?
Reporting period for MRSEC
- Period 4
PubMed: MeSH publication types
- Journal Article