Bipolar Coagulation for Powder Production: Micro-Mixing Inside Droplets

Borra, Jean‐Pascal; Camelot, D.; Chou, Kuo-Chih; Kooyman, Patricia J.; Marijnissen, J.C.M.; Scarlett, B. Florence

doi:10.1016/s0021-8502(98)00757-5

Cited by 52 publications

(31 citation statements)

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“…This effect has been used by several groups to prepare aggregated particles. Borra et al (1999) developed a technique for synthesizing powders via coagulation of particles produced through two opposite polarity electrosprays. In this technique, uncoagulated particles retain a charge and thus can be readily removed by application of an electrostatic filter.…”

Section: Introductionmentioning

confidence: 99%

Coalescence-based assessment of aerosol phase state using dimers prepared through a dual-differential mobility analyzer technique

Rothfuss

Petters

2016

Aerosol Science and Technology

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Viscosity of atmospheric aerosol spans at least 15 orders of magnitude, from thin liquids to glassy solids, with possible concomitant impact on multiple processes of meteorological and/or climatological concern. Recently there has been interest in aerosol phase assessment techniques based upon dimer coalescence. Theoretical treatment suggests discernible reductions in dimer diameter begin when viscosity »10 8 Pa¢s and the dimer is spherical at »10 5 Pa¢s for submicron particles, or the middle range of the semisolid regime. A method using nanoparticle dimers synthesized by utilizing differential mobility analyzers of opposite polarity to produce monomers of opposite charge that subsequently undergo electrostatically mediated coagulation has been developed and is detailed in this work. This method was used to assess the aerosol phase state of several atmospherically relevant organic species and inorganic salts at relative humidity (RH) values ranging between 10% and 100%. Ammonium sulfate, monosodium a-ketoglutaric acid, sodium chloride, and sucrose all displayed RH-dependent phase state. These observed viscous transitions occurred at RH values less than existing deliquescence RH data, a result consistent with existing literature reports of RH-induced structural rearrangements. Fully coalesced and fully uncoalesced diameters could be fitted to single values, indicating that the presented technique is absolute. The method was also used to assess the phase state of dry sucrose aerosol at temperatures between 20 C and 70 C. A phase transition was noted at 63.7 C § 4.4 C, near the glass transition temperature, suggesting the presented method may also be useful for probing phase responses to temperature perturbations.

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Section: Introductionmentioning

confidence: 99%

Coalescence-based assessment of aerosol phase state using dimers prepared through a dual-differential mobility analyzer technique

Rothfuss

Petters

2016

Aerosol Science and Technology

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“…The DNESP method enables to neutralize the droplets coming from different nozzles (via merging two or more droplets with different charges) [6][7][8][9][10][11], and to suppress the deposition on the reactor walls. This study is divided into two parts.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and characterization of TiO2 powders by the double-nozzle electrospray pyrolysis method. Part 1. Refinement and monodispersion of sprayed droplets

Matsubara

Suzuki

Tohno

2012

Comptes Rendus. Chimie

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“…(frames [17][18][19][20], but the uppermost droplet reverses its path (frames [21][22][23][24][25][26][27][28] and collides with the meniscus (frame 29), where they coalesce (frame 30). When considering the physical parameters of this experiment, the reverse movement of a droplet is most probably due to electrostatic attraction, which is only possible if this returning droplet is negatively charged.…”

Section: A Electrospray Characteristics Droplet Charge and Velocitymentioning

confidence: 99%

“…Among these phenomena one can mention the work of Fuchs et al [19,20], who rediscovered Armstrong's [21] rope of water and published a series of papers about this "floating water bridge," the influences of EF on liquid-liquid coalescence [22][23][24][25][26][27], the work of Ristenpart et al [28], who has reported on the noncoalescence of oppositely charged droplets immersed in strong EF, and the deformation of droplets immersed in strong electric fields [29,30]. The last three examples are especially important for the good understanding of this paper; and therefore will be better explored in the following paragraphs.…”

Section: Introductionmentioning

confidence: 99%

Reverse movement and coalescence of water microdroplets in electrohydrodynamic atomization

Agostinho

Fuchs²,

Metz³

et al. 2011

Phys. Rev. E

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When a high voltage is applied to a liquid pumped through a needle, charged microdroplets can be formed, which are carried along the electric field lines. This phenomenon is called electrohydrodynamic atomization (EHDA), or simply electrospray. In this work we show that in the case of water, droplets may reverse their paths flying back toward the liquid meniscus, sometimes making contact with it. Such reverse movement is caused by polarization of the water inside the strong electric field. To understand this phenomenon we developed a way to calculate the droplet charge using its trajectory obtained by high-speed imaging. The values found showed that these droplets are charged between 2.5% and 19% of their Rayleigh limit.

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Bipolar Coagulation for Powder Production: Micro-Mixing Inside Droplets

Cited by 52 publications

References 0 publications

Coalescence-based assessment of aerosol phase state using dimers prepared through a dual-differential mobility analyzer technique

Coalescence-based assessment of aerosol phase state using dimers prepared through a dual-differential mobility analyzer technique

Synthesis and characterization of TiO2 powders by the double-nozzle electrospray pyrolysis method. Part 1. Refinement and monodispersion of sprayed droplets

Reverse movement and coalescence of water microdroplets in electrohydrodynamic atomization

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