A rapid scan vacuum FTIR method for determining diffusion coefficients in viscous and glassy aerosol particles

We report a new method to investigate water transport kinetics in aerosol particles by using rapid scan FTIR spectroscopy combined with a custom-built pulse relative humidity (RH) control system. From real time in situ measurements of RH and composition using high time resolution infrared spectrosco...

Full description

Saved in:
Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2017, Vol.19 (43), p.29177-29186
Main Authors: Zhang, Yun, Cai, Chen, Pang, Shu-Feng, Reid, Jonathan P, Zhang, Yun-Hong
Format: Article
Language:English
Subjects:
Aerosols
Balancing
Condensation
Crystal structure
Crystallinity
Diffusion rate
Dissolution
Fourier transforms
Hygroscopicity
In situ measurement
Infrared spectroscopy
Mass transfer
Mass transport
Relative humidity
Spectrum analysis
Sucrose
Time
Viscosity
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We report a new method to investigate water transport kinetics in aerosol particles by using rapid scan FTIR spectroscopy combined with a custom-built pulse relative humidity (RH) control system. From real time in situ measurements of RH and composition using high time resolution infrared spectroscopy (0.12 s for one spectrum), and through achieving a high rate of RH change (as fast as 60% per second), we are able to investigate the competition between the gas and condensed phase diffusive transport limits of water for particles with mean diameter ∼3 μm and varying phase and viscosity. The characteristic time ( τ ) for equilibration in particle composition following a step change in RH is measured to quantify dissolution timescales for crystalline particles and to probe the kinetics of water evaporation and condensation in amorphous particles. We show that the dissolution kinetics are prompt for crystalline inorganic salt particles following an increase in RH from below to above the deliquescence RH, occurring on a timescale comparable to the timescale of the RH change (
ISSN:1463-9076
1463-9084
DOI:10.1039/c7cp04473a