An unexpected restructuring of combustion soot aggregates by subnanometer coatings of polycyclic aromatic hydrocarbons

Chao Chen, Xiaolong Fan, Tasneem Shaltout, Chong Qiu, Yan Ma, Andrew Goldman, Alexei F. Khalizov

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

We investigated the effect of thin polycyclic aromatic hydrocarbon (PAH) coatings on the structure of soot aggregates. Soot aerosol from an inverted diffusion burner was size classified, thermally denuded, coated with six different PAHs, and then characterized using scanning electron microscopy, light scattering, and mass-mobility measurements. Contrary to our expectation, significant restructuring was observed in the presence of subnanometer layers of pyrene, fluoranthene, and phenanthrene. These PAHs remained in subcooled liquid state in thin films, whereby the liquid layer acted as a lubricant, reducing the force required to initiate the restructuring. Thin layers of PAH of higher melting temperatures (perylene, anthracene, and triphenylene) presumably remained solid because these chemicals induced lesser structural changes. Our results suggest that some of the intrinsic PAH generated during incomplete combustion may induce significant restructuring of soot aggregates, even when present in small quantities, altering the properties and atmospheric impacts of combustion aerosols.

Original languageEnglish (US)
Pages (from-to)11,080-11,088
JournalGeophysical Research Letters
Volume43
Issue number20
DOIs
StatePublished - Oct 28 2016

All Science Journal Classification (ASJC) codes

  • Geophysics
  • Earth and Planetary Sciences(all)

Keywords

  • PAH
  • aerosol
  • aggregates
  • morphology
  • soot

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