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DOI	10.5194/acp-19-3325-2019
	The effect of hydrophobic glassy organic material on the cloud condensation nuclei activity of particles with different morphologies
	Tandon A.; Rothfuss N.E.; Petters M.D.
发表日期	2019
ISSN	16807316
起始页码	3325
结束页码	3339
卷号	19 期号:5
英文摘要	Particles composed of organic and inorganic components can assume core-shell morphologies. The kinetic limitation of water uptake due to the presence of a hydrophobic viscous outer shell may increase the critical supersaturation required to activate such particles into cloud droplets. Here we test this hypothesis through laboratory experiments. Results show that the viscosity of polyethylene particles is 5×106 Pa s at 60 °C. Extrapolation of temperature dependent viscosity measurements suggests that the particles are glassy at room temperature. Cloud condensation nuclei (CCN) activity measurements demonstrate that pure polyethylene particles are CCN inactive at diameters less than 741 nm and 2.5% water supersaturation. Thus, polyethylene is used as proxy for hydrophobic glassy organic material. Ammonium sulfate is used as proxy for hygroscopic CCN active inorganic material. Mixed particles were generated using coagulation of oppositely charged particles; charge-neutral polyethylene-ammonium sulfate dimer particles were then isolated for online observation. Morphology of these dimer particles was varied by heating, such that liquefied polyethylene partially or completely engulfed the ammonium sulfate. Critical supersaturation was measured as a function of dry particle volume, particle morphology, and organic volume fraction. The data show that kinetic limitations do not change the critical supersaturation of 50 nm ammonium sulfate cores coated with polyethylene and polyethylene volume fractions up to 97 %. Based on these results, and a synthesis of literature data, it is suggested that mass transfer limitations by glassy organic shells are unlikely to affect cloud droplet activation near laboratory temperatures. © Author(s) 2019.
语种	英语
scopus关键词	ammonium sulfate; cloud condensation nucleus; coagulation; hydrophobicity; hypothesis testing; organic matter; particulate matter; polymer; viscosity
来源期刊	Atmospheric Chemistry and Physics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/144571
作者单位	Department of Marine Earth and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27695 8208, United States; School of Earth and Environmental Sciences, Central University of Himachal Pradesh, Dharamshala, HP, 176215, India
推荐引用方式 GB/T 7714	Tandon A.,Rothfuss N.E.,Petters M.D.. The effect of hydrophobic glassy organic material on the cloud condensation nuclei activity of particles with different morphologies[J],2019,19(5).
APA	Tandon A.,Rothfuss N.E.,&Petters M.D..(2019).The effect of hydrophobic glassy organic material on the cloud condensation nuclei activity of particles with different morphologies.Atmospheric Chemistry and Physics,19(5).
MLA	Tandon A.,et al."The effect of hydrophobic glassy organic material on the cloud condensation nuclei activity of particles with different morphologies".Atmospheric Chemistry and Physics 19.5(2019).