Interfacial Tensions of Aged Organic Aerosol Particle Mimics Using a Biphasic Microfluidic Platform

Andrew R. Metcalf, Hallie C. Boyer, Cari S. Dutcher

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

Secondary organic aerosol (SOA) particles are a major component of atmospheric particulate matter, yet their formation processes and ambient properties are not well understood. These complex particles often contain multiple interfaces due to internal aqueous- and organic-phase partitioning. Aerosol interfaces can profoundly affect the fate of condensable organic compounds emitted into the atmosphere by altering the way in which ambient organic vapors interact with suspended particles. To accurately predict the evolution of SOA in the atmosphere, we must improve our understanding of aerosol interfaces. In this work, biphasic microscale flows are used to measure interfacial tension of reacting methylglyoxal, formaldehyde, and ammonium sulfate aqueous mixtures with a surrounding oil phase. Our experiments show a suppression of interfacial tension as a function of organic content that remains constant with reaction time for methylglyoxal-ammonium sulfate systems. We also reveal an unexpected time dependence of interfacial tension over a period of 48 h for ternary solutions of both methylglyoxal and formaldehyde in aqueous ammonium sulfate, indicating a more complicated behavior of surface activity where there is competition among dissolved organics. From these interfacial tension measurements, the morphology of aged atmospheric aerosols with internal liquid-liquid phase separation is inferred.

Original languageEnglish (US)
Pages (from-to)1251-1259
Number of pages9
JournalEnvironmental Science and Technology
Volume50
Issue number3
DOIs
StatePublished - Feb 2 2016

Bibliographical note

Publisher Copyright:
© 2015 American Chemical Society.

How much support was provided by MRSEC?

  • Shared

Reporting period for MRSEC

  • Period 2

PubMed: MeSH publication types

  • Journal Article
  • Research Support, U.S. Gov't, Non-P.H.S.

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