Controllable geometry-mediated droplet fission using “off-the-shelf” capillary microfluidics device

Droplet fission has gained notable interest in drug delivery applications due to its ability to perform parallel operations in single device. Hitherto, droplet flow behavior in a 3D constriction was scarcely investigated. This study aims to investigate droplets fission inside a 3D bi-planar multifurcated microfluidic device. The flow behavior and droplet size distribution were studied in trifurcated microchannels using distilled water as dispersed phase (1 mPa·s) and olive oil (68 mPa·s) as continuous phase. Various sizes of subordinate daughter droplets were manipulated passively through the modulation of flowrate ratio (Q) (0.15 < Q < 3.33). Overall, we found droplet size coefficient of variations (CV%) ranging from 0.72% to 69%. Highly monodispersed droplets were formed at the upstream T-junction (CV% < 2%) while the droplet fission process was unstable at higher flowrate ratio (Q > 0.4) as they travel downstream (1.5% < CV% < 69%) to splitting junctions. Complex responses to the non-monotonic behavior of mean droplet size was found at the downstream boundaries, which arose from the deformations under nonuniform flow condition. CFD was used as a tool to study the preliminary maximum velocity (Umax) profile for the symmetrical (0.01334 m/s < Umax < 0.0153 m/s) and asymmetrical branched channels (0.0223 m/s< Umax < 0.00438 m/s), thus complementing the experimental model studies.

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Generation of secondary droplets in coalescence of a drop at a liquid–liquid interface

Journal of Fluid Mechanics ◽

10.1017/s0022112010000662 ◽

2010 ◽

Vol 655 ◽

pp. 72-104 ◽

Cited By ~ 54

Author(s):

B. RAY ◽

G. BISWAS ◽

A. SHARMA

Keyword(s):

Critical Value ◽

Bond Number ◽

Viscous Force ◽

Time Range ◽

Main Body ◽

Ohnesorge Number ◽

Partial Coalescence ◽

Daughter Droplets ◽

Secondary Droplets ◽

Secondary Drop

When a droplet of liquid 1 falls through liquid 2 to eventually hit the liquid 2–liquid 1 interface, its initial impact on the interface can produce daughter droplets of liquid 1. In some cases, a partial coalescence cascade governed by self-similar capillary-inertial dynamics is observed, where the fall of the secondary droplets in turn continues to produce further daughter droplets. Results show that inertia and interfacial surface tension forces largely govern the process of partial coalescence. The partial coalescence is suppressed by the viscous force when Ohnesorge number is below a critical value and also by gravity force when Bond number exceeds a critical value. Generation of secondary drop is observed for systems of lower Ohnesorge number for liquid 1, lower and intermediate Ohnesorge number for liquid 2 and for low and intermediate values of Bond number. Whenever the horizontal momentum in the liquid column is more than the vertical momentum, secondary drop is formed. A transition regime from partial to complete coalescence is obtained when the neck radius oscillates twice. In this regime, the main body of the column can be fitted to power-law scaling model within a specific time range. We investigated the conditions and the outcome of these coalescence events based on numerical simulations using a coupled level set and volume of fluid method (CLSVOF).

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Droplet Formation and Fission in Shear-Thinning/Newtonian Multiphase System Using Bilayer Bifurcating Microchannel

Journal of Heat Transfer ◽

10.1115/1.4037338 ◽

2017 ◽

Vol 140 (1) ◽

Cited By ~ 7

Author(s):

Yong Ren ◽

Kai Seng Koh ◽

Jit Kai Chin ◽

Jing Wang ◽

Conghua Wen ◽

...

Keyword(s):

Shear Thinning ◽

Droplet Formation ◽

Newtonian Fluids ◽

Model Systems ◽

Multiphase System ◽

Blood Capillaries ◽

Two Systems ◽

Flow Through ◽

Newtonian System ◽

Droplet Fission

With a novel platform of bilayer polydimethylsiloxane microchannel formed by bifurcating junction, we aim to investigate droplet formation and fission in a multiphase system with complex three-dimensional (3D) structure and understand the variations in mechanism associated with droplet formation and fission in the microstructure between shear-thinning/Newtonian system versus Newtonian/Newtonian system. The investigation concentrates on shear-thinning fluid because it is one of the most ubiquitous rheological properties of non-Newtonian fluids. Sodium carboxymethyl cellulose (CMC) solution and silicone oil have been used as model fluids and numerical model has been established to characterize the shear-thinning effect in formation of CMC-in-oil emulsions, as well as breakup dynamics when droplets flow through 3D bifurcating junction. The droplet volume and generation rate have been compared between two systems at the same Weber number and capillary number. Variation in droplet fission has been found between two systems, demonstrating that the shear-thinning property and confining geometric boundaries significantly affect the deformation and breakup of each mother droplet into two daughter droplets at bifurcating junction. The understanding of the droplet fission in the novel microstructure will enable more versatile control over the emulsion formation and fission when non-Newtonian fluids are involved. The model systems in the study can be further developed to investigate the mechanical property of emulsion templated particles such as drug encapsulated microcapsules when they flow through complex media structures, such as blood capillaries or the porous tissue structure, which feature with bifurcating junction.

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Microfluidic Combinatorial Screening Platform

ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels ◽

10.1115/icnmm2012-73159 ◽

2012 ◽

Author(s):

Helena Zec ◽

Tushar D. Rane ◽

Wen-Chy Chu ◽

Tza-Huei Wang

Keyword(s):

High Throughput ◽

Microfluidic Chip ◽

Linear Array ◽

Large Array ◽

Snp Detection ◽

Combinatorial Screening ◽

Biological Assays ◽

Reagent Consumption ◽

Daughter Droplets ◽

Screening Platform

We propose a microfluidic droplet-based platform that accepts an unlimited number of sample plugs from a multi-well plate, performs splitting of these sample droplets into smaller daughter droplets and subsequent synchronization-free, reliable fusion of sample daughter droplets with multiple reagents simultaneously. This system consists of two components: 1) a custom autosampler which generates a linear array of sub-microliter plugs in a microcapillary from a multi-well plate and 2) A microfluidic chip with channels for sample plug introduction, reagent merging and droplet incubation. This novel system generates large arrays of heterogeneous droplets from hundreds to thousands of samples while concurrently screening these arrays against a large array of reagents. This high throughput system minimizes sample and reagent consumption and can be applied to a gamut of biological assays, ranging from SNP detection to forensic screening.

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Electrified droplet fission and the Rayleigh limit

Langmuir ◽

10.1021/la00086a016 ◽

1989 ◽

Vol 5 (2) ◽

pp. 376-384 ◽

Cited By ~ 156

Author(s):

Daniel C. Taflin ◽

Timothy L. Ward ◽

E. James Davis

Keyword(s):

Rayleigh Limit ◽

Droplet Fission

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Comments on Papers by Ryce et al. on The Electrostatic Dispersion of Liquids

Canadian Journal of Physics ◽

10.1139/p74-139 ◽

1974 ◽

Vol 52 (11) ◽

pp. 1046-1047

Author(s):

V. E. Krohn

Keyword(s):

Binary Fission ◽

Electronic Charge ◽

Daughter Droplets ◽

Low Charge ◽

Electrostatic Dispersion ◽

Rayleigh Limit

It is noted that all drops carrying more than one unit of electronic charge (on their surface) are either metastable or unstable and that the energetically most favored mode of binary fission does not result in daughter droplets with charges exceeding the Rayleigh limit, although this limit would be closely approached by the smaller daughter droplet if this mode of fission were induced in drops of low charge relative to the Rayleigh limit. Also, it is suggested that the secondary fission observed by Ryce and Patriarche probably followed a primary fission which was highly asymmetric because of perturbations existing when the original drop was created.

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Numerical study of droplet breakup in an asymmetric T-junction microchannel with different cross-section ratios

International Journal of Modern Physics C ◽

10.1142/s0129183122500231 ◽

2021 ◽

pp. 2250023

Author(s):

Milad Isanejad ◽

Keivan Fallah

Keyword(s):

Cross Section ◽

Numerical Study ◽

Three Dimensional ◽

Droplet Breakup ◽

Width Ratio ◽

Two Phase ◽

Droplet Motion ◽

Daughter Droplets ◽

Breakup Time ◽

Good Agreement

In this study, numerical simulations are conducted to investigate droplet breakup in an asymmetric [Formula: see text]-junction microchannel with different cross-section ratios. To this approach, a two-phase model based on the volume of fluid (VOF) method is adopted to study the three-dimensional feature of droplet motion inside [Formula: see text]-junctions. The comparison reveals that the present results are in good agreement with previous studies. The effects of the capillary number (Ca), the non-dimensional droplet length ([Formula: see text]), and the non-dimensional width ratio ([Formula: see text]) on the breakup time and splitting ratio of daughter droplets are studied. Five distinct regimes are observed involving the non-breakup, breakup with tunnel, breakup without tunnel, asymmetric breakup, and sorting. Achieved results indicate that the time of breakup ([Formula: see text]) increases about 15% when the Ca is increased from 0.0134 to 0.0268 (about 100%). It is also found that the mass center of the mother droplet in the primary channel is shifted to a larger wide branch, which facilitates the asymmetric breakup of the droplet in a [Formula: see text]-junction microchannel.

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Breakdown of scaling in droplet fission at high Reynolds number

Physics of Fluids ◽

10.1063/1.869279 ◽

1997 ◽

Vol 9 (6) ◽

pp. 1573-1590 ◽

Cited By ~ 92

Author(s):

Michael P. Brenner ◽

Jens Eggers ◽

Kathy Joseph ◽

Sidney R. Nagel ◽

X. D. Shi

Keyword(s):

Reynolds Number ◽

High Reynolds Number ◽

High Reynolds ◽

Droplet Fission

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Inhibition of the Finite-Time Singularity during Droplet Fission of a Polymeric Fluid

Physical Review Letters ◽

10.1103/physrevlett.86.3558 ◽

2001 ◽

Vol 86 (16) ◽

pp. 3558-3561 ◽

Cited By ~ 113

Author(s):

Y. Amarouchene ◽

D. Bonn ◽

J. Meunier ◽

H. Kellay

Keyword(s):

Finite Time ◽

Time Singularity ◽

Polymeric Fluid ◽

Finite Time Singularity ◽

Droplet Fission

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Droplet breakup in the square microchannel with a short square constriction to generate slug flow

10.22541/au.164168564.48476235/v1 ◽

2022 ◽

Author(s):

Xiaoda Wang ◽

Yuanyuan Liu ◽

Dayu Liu ◽

Xuehui Ge ◽

Ling Li ◽

...

Keyword(s):

Droplet Size ◽

Slug Flow ◽

Empirical Equation ◽

Industrial Applications ◽

Droplet Breakup ◽

Mechanism Analysis ◽

Operation Conditions ◽

Comparison Results ◽

Daughter Droplets ◽

Square Microchannel

Droplet breakup in micro-constrictions is an important phenomenon in industrial applications. This work aimed to investigate the droplet breakup in the square microchannel with a short square constriction to generate the slug flow, which drew little attention before. Mechanism analysis indicated that this breakup process included the shear-force-dominated, squeezing-force-dominated, and pinch-off stages. Non-uniform daughter droplets were generated in the constriction with their interface restricted in the horizontal and perpendicular directions by the microchannel walls. The average relative deviation of the daughter droplet size was < 30%, much lower than that for the breakup with the daughter droplet restricted only in one direction. An empirical equation with a deviation of < 20% was provided to show the dependence of the daughter droplet size on the operation conditions. The comparison results suggested that the different restriction effects of microchannel wall on daughter droplets led to the different breakup mechanisms in different constrictions.

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