Direct surface tension measurements of individual sub-micrometer particles using atomic force microscopy

TitleDirect surface tension measurements of individual sub-micrometer particles using atomic force microscopy
Publication TypeJournal Article
Year of Publication2017
AuthorsLee H.D, Estillore A.D, Morris H.S, Ray K.K, Alejandro A., Grassian VH, Tivanski A.V
JournalJournal of Physical Chemistry A
Date Published2017/11
Type of ArticleArticle
ISBN Number1089-5639
Accession NumberWOS:000414622800014
Keywordsammonium-sulfate; aqueous-solutions; atmospheric aerosols; dicarboxylic-acids; hygroscopic behavior; natural aerosols; organic-compounds; primary marine aerosol; sea-spray aerosol; viscosity

Understanding the role of sea spray aerosol (SSA) on climate and the environment is of great interest due to their high number concentration throughout the Earth's atmosphere. Despite being of fundamental importance, direct surface tension measurements of SSA relevant sub-micrometer particles are rare, largely due to their extremely small volumes. Herein, atomic force microscopy (AFM) is used to directly measure the surface tension of individual sub-micrometer SSA particle mimics at ambient temperature and varying relative humidity (RH). Specifically, we probed both atmospherically relevant and fundamentally important model systems including electrolyte salts, dicarboxylic acids, and saccharides as single components and mixtures. Our results show that the single particle surface tension depends on RH or solute mole percentage and chemical composition. Moreover, for liquid droplets at and below 100 Pa s in viscosity, or at corresponding RH, we show good agreement between the AFM single particle and the bulk solution surface tension measurements at overlapping concentration ranges. Thus, direct surface tension measurements of individual particles using AFM is shown over a wide range of chemical systems as a function of RH, solute mole percentage, and viscosity than previously reported.

Short TitleJ. Phys. Chem. A
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