Changing shapes and implied viscosities of suspended submicron particles

The change in shape of atmospherically relevant organic particles is used to estimate the viscosity of the particle material without the need for removal from aerosol suspension. The dynamic shape factors χ of particles produced by α-pinene ozonolysis in a flow tube reactor, under conditions of part...

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Main Authors: Zhang, Y., Sanchez, M. S., Douet, C., Wang, Y., Bateman, A. P., Gong, Z., Kuwata, Mikinori, Renbaum-Wolff, L., Sato, B. B., Liu, P. F., Bertram, A. K., Geiger, F. M., Martin, S. T.
Other Authors: School of Physical and Mathematical Sciences
Format: Article
Language:English
Published: 2015
Online Access:https://hdl.handle.net/10356/79273
http://hdl.handle.net/10220/38713
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-792732020-09-26T21:29:13Z Changing shapes and implied viscosities of suspended submicron particles Zhang, Y. Sanchez, M. S. Douet, C. Wang, Y. Bateman, A. P. Gong, Z. Kuwata, Mikinori Renbaum-Wolff, L. Sato, B. B. Liu, P. F. Bertram, A. K. Geiger, F. M. Martin, S. T. School of Physical and Mathematical Sciences Earth Observatory of Singapore The change in shape of atmospherically relevant organic particles is used to estimate the viscosity of the particle material without the need for removal from aerosol suspension. The dynamic shape factors χ of particles produced by α-pinene ozonolysis in a flow tube reactor, under conditions of particle coagulation, were measured while altering the relative humidity (RH) downstream of the flow tube. As relative humidity was increased, the results showed that χ could change from 1.27 to 1.02, corresponding to a transition from aspherical to nearly spherical shapes. The shape change could occur at elevated RH because the organic material had decreased viscosity and was therefore able to flow to form spherical shapes, as favored by the minimization of surface area. Numerical modeling was used to estimate the particle viscosity associated with this flow. Based on particle diameter and RH exposure time, the viscosity dropped from 10(8.7±2.0) to 10(7.0±2.0) Pa s (two sigma) for an increase in RH from < 5 to 58 % at 293 K. These results imply that the equilibration of the chemical composition of the particle phase with the gas phase can shift from hours at mid-range RH to days at low RH. Published version 2015-09-18T08:35:47Z 2019-12-06T13:21:21Z 2015-09-18T08:35:47Z 2019-12-06T13:21:21Z 2015 2015 Journal Article Zhang, Y., Sanchez, M. S., Douet, C., Wang, Y., Bateman, A. P., Gong, Z., et al. (2015). Changing shapes and implied viscosities of suspended submicron particles. Atmospheric Chemistry and Physics, 15(14), 7819-7829. 1680-7324 https://hdl.handle.net/10356/79273 http://hdl.handle.net/10220/38713 10.5194/acp-15-7819-2015 en Atmospheric Chemistry and Physics © Author(s) 2015. This work is distributed under the Creative Commons Attribution 3.0 License. application/pdf
institution Nanyang Technological University
building NTU Library
country Singapore
collection DR-NTU
language English
description The change in shape of atmospherically relevant organic particles is used to estimate the viscosity of the particle material without the need for removal from aerosol suspension. The dynamic shape factors χ of particles produced by α-pinene ozonolysis in a flow tube reactor, under conditions of particle coagulation, were measured while altering the relative humidity (RH) downstream of the flow tube. As relative humidity was increased, the results showed that χ could change from 1.27 to 1.02, corresponding to a transition from aspherical to nearly spherical shapes. The shape change could occur at elevated RH because the organic material had decreased viscosity and was therefore able to flow to form spherical shapes, as favored by the minimization of surface area. Numerical modeling was used to estimate the particle viscosity associated with this flow. Based on particle diameter and RH exposure time, the viscosity dropped from 10(8.7±2.0) to 10(7.0±2.0) Pa s (two sigma) for an increase in RH from < 5 to 58 % at 293 K. These results imply that the equilibration of the chemical composition of the particle phase with the gas phase can shift from hours at mid-range RH to days at low RH.
author2 School of Physical and Mathematical Sciences
author_facet School of Physical and Mathematical Sciences
Zhang, Y.
Sanchez, M. S.
Douet, C.
Wang, Y.
Bateman, A. P.
Gong, Z.
Kuwata, Mikinori
Renbaum-Wolff, L.
Sato, B. B.
Liu, P. F.
Bertram, A. K.
Geiger, F. M.
Martin, S. T.
format Article
author Zhang, Y.
Sanchez, M. S.
Douet, C.
Wang, Y.
Bateman, A. P.
Gong, Z.
Kuwata, Mikinori
Renbaum-Wolff, L.
Sato, B. B.
Liu, P. F.
Bertram, A. K.
Geiger, F. M.
Martin, S. T.
spellingShingle Zhang, Y.
Sanchez, M. S.
Douet, C.
Wang, Y.
Bateman, A. P.
Gong, Z.
Kuwata, Mikinori
Renbaum-Wolff, L.
Sato, B. B.
Liu, P. F.
Bertram, A. K.
Geiger, F. M.
Martin, S. T.
Changing shapes and implied viscosities of suspended submicron particles
author_sort Zhang, Y.
title Changing shapes and implied viscosities of suspended submicron particles
title_short Changing shapes and implied viscosities of suspended submicron particles
title_full Changing shapes and implied viscosities of suspended submicron particles
title_fullStr Changing shapes and implied viscosities of suspended submicron particles
title_full_unstemmed Changing shapes and implied viscosities of suspended submicron particles
title_sort changing shapes and implied viscosities of suspended submicron particles
publishDate 2015
url https://hdl.handle.net/10356/79273
http://hdl.handle.net/10220/38713
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