Aerosol Droplet Surface Measurement Methods

Abstract

Aerosol droplets play a critical role in the development of weather patterns yet are notoriously difficult to analyze because of their small size, transient nature and potentially complex composition. As a result, there has been a surge in recent years of analysis techniques aimed at the study of aerosol droplets, namely of their surface tension properties, which is suspected of playing a great role in aerosol/cloud growth and subsequently impacting the resulting weather patterns. To capture the state of the field at this key time, we have collected and described some of the most relevant and influential studies, with a focus on those that have had the most impact. This review will present and describe the most used analytical techniques for studying the surface tension of micrometer sized aqueous droplets with an eye towards historical trends and how the current techniques are posed to revolutionize the field.

Emerging investigator series: surfactants, films, and coatings on atmospheric aerosol particles: a review

“…207 Several recent techniques have been designed specifically for measuring the surface tension of atmospherically relevant droplets and aerosol particles. 208 For example, Lee and Tivanski 209 have reviewed applications of AFM to probe the physical and chemical properties of aerosol particles, including their surface tension.…”

“…MD simulations have been used to model surface tension for surfactant solutions containing nonionic surfactants (fatty alcohols, 219 polyethylene glycol, 220 tetraethyleneglycol 221 ), cationic surfactants (dodecyl trimethyl ammonium chloride 219 ), and anionic surfactants (dodecylsulfate 219,222,223 ). For more information about experimental and computational techniques for measuring and modeling surface tension, see the 2021 review by Mott et al 208…”

Evidence of Surface-Tension Lowering of Atmospheric Aerosols by Organics from Field Observations in an Urban Atmosphere: Relation to Particle Size and Chemical Composition

“…However, measuring surface tension is not a routine operation in field campaigns, and the role of surfactants in CCN activity is not well quantified by field observations. Most work and techniques focus on laboratory measurements of surface tension for droplets with specified size and/or known chemical composition. ,− Surface tension can also be estimated by thermodynamical, statistical, and empirical models built upon and verified by laboratory and observational data. ,,,,,− However, models require knowledge of droplet size, composition, and activity coefficient, which are usually very complex and not measured in field campaigns. Also, only 10–30% of the organic mass is identified at a molecular level .…”