Influence of organic films on the evaporation and condensation of water in aerosol

Research output: Contribution to journalArticle (Academic Journal)

88 Citations (Scopus)
395 Downloads (Pure)

Abstract

Uncertainties in quantifying the kinetics of evaporation and condensation of water fromatmospheric aerosol are a significant contributor to the uncertainty in predicting cloud droplet number and the indirect effect of aerosols on climate. The influence of aerosol particle surface composition, particularly the impact of surface active organic films, on the condensation and evaporation coefficients remains ambiguous. Here, we report measurements of the influence of organic films on the evaporation and condensation of water from aerosol particles. Significant reductions in the evaporation coefficient are shown to result when condensed films are formed by monolayers of long-chain alcohols [CnH(2n+1)OH], with the value decreasing from 2.4 x 10(-3) to 1.7 x 10(-5) as n increases from 12 to 17. Temperature-dependent measurements confirm that a condensed film of long-range order must be formed to suppress the evaporation coefficient below 0.05. The condensation of water on a droplet coated in a condensed film is shown to be fast, with strong coherence of the long-chain alcohol molecules leading to islanding as the water droplet grows, opening up broad areas of uncoated surface on which water can condense rapidly. We conclude that multicomponent composition of organic films on the surface of atmospheric aerosol particles is likely to preclude the formation of condensed films and that the kinetics of water condensation during the activation of aerosol to form cloud droplets is likely to remain rapid.

Original languageEnglish
Pages (from-to)8807-8812
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume110
Issue number22
Early online date23 Apr 2013
DOIs
Publication statusPublished - 28 May 2013

Keywords

  • water transport
  • organic monolayers
  • mass accommodation
  • surface films
  • MASS ACCOMMODATION COEFFICIENT
  • GAS-LIQUID INTERFACES
  • MOLECULAR-DYNAMICS
  • SURFACE
  • MONOLAYERS
  • GENERATION
  • PARTICLES
  • DROPLETS
  • VAPOR
  • OCTADECANOL

Fingerprint Dive into the research topics of 'Influence of organic films on the evaporation and condensation of water in aerosol'. Together they form a unique fingerprint.

Cite this