title: Influence of Functional Groups on the Viscosity of Organic Aerosol.
abstract: Organic aerosols can exist in highly viscous or glassy phase states. A viscosity database for organic compounds with atmospherically relevant functional groups is compiled and analyzed to quantify the influence of number and location of functional groups on viscosity. For weakly functionalized compounds the trend in viscosity sensitivity to functional group addition is carboxylic acid (COOH) ≈ hydroxyl (OH) > nitrate (ONO2) > carbonyl (CO) ≈ ester (COO) > methylene (CH2). Sensitivities to group addition increase with greater levels of prior functionalization and decreasing temperature. For carboxylic acids a sharp increase in sensitivity is likely present already at the second addition at room temperature. Ring structures increase viscosity relative to linear structures. Sensitivities are correlated with analogously derived sensitivities of vapor pressure reduction. This may be exploited in the future to predict viscosity in numerical models by piggybacking on schemes that track the evolution of organic aerosol volatility with age.
authors.affiliation: Department of Marine Earth and Atmospheric Sciences, North Carolina State University , Raleigh, North Carolina 27695, United States.
authors.forename: Nicholas E
authors.identifier: 0000-0002-1495-1902
authors.initials: NE
authors.lastname: Rothfuss
authors.affiliation: Department of Marine Earth and Atmospheric Sciences, North Carolina State University , Raleigh, North Carolina 27695, United States.
authors.forename: Markus D
authors.identifier: 0000-0002-4082-1693
authors.initials: MD
authors.lastname: Petters
mesh_terms: D000336:Aerosols / Q000737:chemistry*; D005740:Gases; D009930:Organic Chemicals / Q000737:chemistry*; D014783:Viscosity; D014835:Volatilization
chemical_list: D000336:Aerosols; D005740:Gases; D009930:Organic Chemicals