Charge induced stability of water droplets in subsaturated environment

Nielsen, Johannes K.; Maus, C.; Rzesanke, Daniel; Leisner, Thomas

doi:10.5194/acp-11-2031-2011

Cited by 39 publications

(34 citation statements)

References 16 publications

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“…Nielsen et al . 69 have recently shown size–charge association for the case of a charged, micron-size pure water droplet. It was demonstrated that the surface charge effectively increases surface tension leading to a reduced evaporation rate.…”

Section: Resultsmentioning

confidence: 99%

A chemical free, nanotechnology-based method for airborne bacterial inactivation using engineered water nanostructures

Pyrgiotakis¹,

McDevitt²,

Bordini³

et al. 2014

Environ. Sci.: Nano

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Airborne pathogens are associated with the spread of infectious diseases and increased morbidity and mortality. Herein we present an emerging chemical free, nanotechnology-based method for airborne pathogen inactivation. This technique is based on transforming atmospheric water vapor into Engineered Water Nano-Structures (EWNS) via electrospray. The generated EWNS possess a unique set of physical, chemical, morphological and biological properties. Their average size is 25 nm and they contain reactive oxygen species (ROS) such as hydroxyl and superoxide radicals. In addition, EWNS are highly electrically charged (10 electrons per particle on average). A link between their electric charge and the reduction of their evaporation rate was illustrated resulting in an extended lifetime (over an hour) at room conditions. Furthermore, it was clearly demonstrated that the EWNS have the ability to interact with and inactivate airborne bacteria. Finally, inhaled EWNS were found to have minimal toxicological effects, as illustrated in an acute in-vivo inhalation study using a mouse model. In conclusion, this novel, chemical free, nanotechnology-based method has the potential to be used in the battle against airborne infectious diseases.

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Section: Resultsmentioning

confidence: 99%

A chemical free, nanotechnology-based method for airborne bacterial inactivation using engineered water nanostructures

Pyrgiotakis¹,

McDevitt²,

Bordini³

et al. 2014

Environ. Sci.: Nano

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“…It has been shown by Nielsen et al (2011) that in certain cases, the influence of charge can have an appreciable effect on both the evaporation rate and the equilibrium state of a droplet. In order to determine the effects of the charge on droplet evaporation, we conducted measurements using the lowest concentration (which reaches the smallest size) of glycerol and a range of induction voltages spanning 400-800 V ( Figure 11).…”

Section: Model Treatmentmentioning

confidence: 99%

Time-Resolved Measurements of the Evaporation of Volatile Components from Single Aerosol Droplets

Davies

Haddrell

Reid

2012

Aerosol Science and Technology

101

147

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A strategy for examining the dynamic hygroscopic response of single aerosol particles is reported, allowing a direct investigation of the interplay of thermodynamic and kinetic factors regulating the time dependence of particle size. In particular, we investigate the rapid evaporation of water from water-glycerol droplets, measuring the evolving size with a time resolution of <10 ms (with as low as 2.5 ms being possible) over a time range from subsecond to many hours. Measurements can be made on sequential droplets generated from a droplet-on-demand generator, and a reproducibility of better than ±0.25 µm in droplet size over tens of events can be achieved at any resolved time point considered during an evaporation process lasting >2 s. The time-dependent measurements of evolving droplet size are compared with an analytical treatment of the evaporation process. Excellent agreement between measurements and simulations is found over a wide range of starting droplet compositions. The benefits of using this approach for investigating water transport within the bulk of an aerosol particle or to/from the droplet surface are discussed.

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“…We have considered the influence of droplet charge on evaporation rates in previous work, 32 showing it to have negligible impact at the imbalance of positive and negative ions induced in the droplets studied in these experiments. 44 The mass transfer enhancement resulting from the flowing gas surrounding the droplet is accounted for by the inclusion of a Sherwood number (Sh) scaling of the mass flux. 33,43 The thermophysical parameters that appear in the mass flux treatment and their uncertainties have been thoroughly discussed in previous publications.…”

Section: Methodsmentioning

confidence: 99%

Accurate Measurements of Aerosol Hygroscopic Growth over a Wide Range in Relative Humidity

et al. 2016

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Using a comparative evaporation kinetics approach, we describe a new and accurate method for determining the equilibrium hygroscopic growth of aerosol droplets. The time-evolving size of an aqueous droplet, as it evaporates to a steady size and composition that is in equilibrium with the gas phase relative humidity, is used to determine the time-dependent mass flux of water, yielding information on the vapor pressure of water above the droplet surface at every instant in time. Accurate characterization of the gas phase relative humidity is provided from a control measurement of the evaporation profile of a droplet of know equilibrium properties, either a pure water droplet or a sodium chloride droplet. In combination, and by comparison with simulations that account for both the heat and mass transport governing the droplet evaporation kinetics, these measurements allow accurate retrieval of the equilibrium properties of the solution droplet (i.e., the variations with water activity in the mass fraction of solute, diameter growth factor, osmotic coefficient or number of water molecules per solute molecule). Hygroscopicity measurements can be made over a wide range in water activity (from >0.99 to, in principle, <0.05) on time scales of <10 s for droplets containing involatile or volatile solutes. The approach is benchmarked for binary and ternary inorganic solution aerosols with typical uncertainties in water activity of <±0.2% at water activities >0.9 and ∼±1% below 80% RH, and maximum uncertainties in diameter growth factor of ±0.7%. For all of the inorganic systems examined, the time-dependent data are consistent with large values of the mass accommodation (or evaporation) coefficient (>0.1).

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Charge induced stability of water droplets in subsaturated environment

Cited by 39 publications

References 16 publications

A chemical free, nanotechnology-based method for airborne bacterial inactivation using engineered water nanostructures

A chemical free, nanotechnology-based method for airborne bacterial inactivation using engineered water nanostructures

Time-Resolved Measurements of the Evaporation of Volatile Components from Single Aerosol Droplets

Accurate Measurements of Aerosol Hygroscopic Growth over a Wide Range in Relative Humidity

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