Microdroplet generation in gaseous and liquid environments

Ben-Tzvi, Pinhas; Rone, Will

doi:10.1007/s00542-009-0962-7

Cited by 35 publications

(17 citation statements)

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“…In many of these devices, one or multiple streams focus another stream by influencing its fluidic path. If the streams comprise immiscible fluids, the flow interactions lead to formation of droplets or bubbles, which have been studied extensively (Anna et al 2003;Thorsen et al 2001;Whitesides 2006;Ben-Tzvi and Rone 2010). Herein, we examine the convergence of two miscible fluidic streams to understand the dynamics of flow focusing.…”

Section: Introductionmentioning

confidence: 98%

Parameters affecting the shape of a hydrodynamically focused stream

Nasir

Mott

Kennedy

et al. 2011

Microfluid Nanofluid

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Even at low Reynolds numbers, momentum can impact the shape of hydrodynamically focused flow. Both theoretical and experimental characterization of hydrodynamic focusing in microchannels at Reynolds numbers B25 revealed the important parameters that affect the shape of the focused layer. A series of symmetric and asymmetric microfluidic channels with two converging streams were fabricated with different angles of confluence at the junction. The channels were used to study the characteristics of Y-type microchannels for flow-focusing. Computational analysis and experimental results gathered using confocal microscopy and particle image velocimetry indicated that the orientation of the sheath and the sample stream inlets, as well as the absolute flow velocities, determine the curvature in the concentration distribution of the focused stream. Decreasing the angle of confluence between sheath and sample, as well as reducing the overall Reynolds number, resulted in a flat interface between sheath and focused fluids. Alignment of the faster flowing sheath fluid channel with the main channel also reduced the inertial effects and produced a focused stream with a flat concentration profile. Control over the shape of the focused stream is important in many biosensors and lab-on-a-chip devices that rely on hydrodynamic focusing for increased detection sensitivity.

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Section: Introductionmentioning

confidence: 98%

Parameters affecting the shape of a hydrodynamically focused stream

Nasir

Mott

Kennedy

et al. 2011

Microfluid Nanofluid

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“…Drop-on-demand (DOD) technologies for micro-droplet deposition have been widely used in various fields owing to high precision and automation [1][2][3][4][5]; applications range from additive manufacturing [6][7][8][9][10] and electronics applications [11,12] to emerging fields such as pharmacology [13], pathology [14], tissue engineering [15][16][17][18], and biosensor manufacturing [19]. For instance, DOD mode micro-droplet deposition has been employed for high-throughput screening (HTS) applications to increase the efficiency of drug screening and delivery [20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Alternating Force Based Drop-on-Demand Microdroplet Formation and Three-Dimensional Deposition

Zhao

Yan

Yao

et al. 2015

Journal of Manufacturing Science and Engineering

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AbstractsDrop-on-demand (DOD) micro-droplet formation and deposition play an important role in additive manufacturing, particularly in printing of 3D in vitro biological models for pharmacological and pathological studies, for tissue engineering and regenerative medicine applications, and for building of cell-integrated micro-fluidic devices. In development of a DOD based micro-droplet deposition process for 3D cell printing, the droplet formation, controlled on-demand deposition and at the single cell level, and most importantly, maintaining the viability and functionality of the cells during and after the printing, are all remaining to be challenged. This report presents our recent study on developing a novel DOD based micro-droplet deposition process for 3D Printing by utilization of an alternating viscous & inertial force jetting mechanism. The results include an analysis of droplet formation mechanism, the system configuration, and experimental study of the effects of process parameters on micro-droplet formation. Sodium Alginate solutions are used for micro-droplet formation and deposition. Key process parameters include actuation signal waveforms, nozzle dimensional features, and solution SUN A c c e p t e d M a n u s c r i p t N o t C o p y e d i t e dviscosity. Sizes of formed micro-droplets are examined by measuring the droplet diameter and velocity. Resultsshow that by utilizing a nozzle at a 45μm diameter, the size of the formed micro-droplets are in the range of 52~72μm in diameter and 0.4~2.0m/s in jetting speed, respectively. Reproducibility of the system is also examined and the results show that the deviation of the formed micro-droplet diameter and the droplet deposition accuracy are within 6% and 6.2μm range, respectively. Experimental results demonstrate a high controllability and precision for the developed DOD micro-droplet deposition system with a potential for precise cell printing.

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“…This pulse briefly compresses the capillary and causes a small portion of liquid to exit the nearby capillary orifice. [2][3][4] The size of the resulting liquid droplet is generally determined by the capillary inner diameter, the characteristics of the applied potential pulse (including pulsewidth and amplitude), in addition to the physical properties of the liquid (e.g. viscosity and surface tension).…”

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confidence: 99%

Drop-on-demand microdroplet generation: a very stable platform for single-droplet experimentation

2016

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. (2016). Drop-on-demand microdroplet generation: a very stable platform for single-droplet experimentation. RSC Advances: an international journal to further the chemical sciences, 6 (65), 60215-60222. Drop-on-demand microdroplet generation: a very stable platform for single-droplet experimentation AbstractThis paper reports the performance of drop-on-demand piezo-activated microdroplet generation investigated using microdroplet cavity enhanced fluorescence spectroscopy. Aqueous microdroplets, doped with a fluorescent dye, exhibit fluorescence spectra that are dominated by cavity resonances (termed whispering gallery modes) that, when analysed using Mie theory, allow for the determination of the radius of each microdroplet. The effect of controlled changes in the square-wave droplet generator voltage waveform on droplet size is investigated as well as the size reproducibility of successive microdroplets. Furthermore, using custom square-wave waveforms, microdroplet radii spanning ∼10 to 30 μm are produced from the same droplet dispenser. These non-standard waveforms do not sacrifice the reproducibility of microdroplet generation with <1% size variation. Tuning the single square-wave pulsewidths induces predictable changes in the microdroplet radius and steps on the order of tens of nanometers are detectable. With finer voltage adjustments the microdroplet size is essentially tunable. These results confirm the extremely high stability and reproducibility of on-demand microdroplet generation and that precise size control is possible, rendering them suitable platforms for many applications in fundamental and applied research in areas including mass spectrometry, aerosol investigations and liquid-phase chemistry Aqueous microdroplets, doped with a fluorescent dye, exhibit fluorescence spectra that are dominated by cavity resonances (termed whispering gallery modes) that, when analysed using Mie theory, allow for the determination of the radius of each microdroplet. The effect of controlled changes in the square-wave droplet generator voltage waveform on droplet size is investigated as well as the size reproducibility of successive microdroplets. Furthermore, using custom square-wave waveforms, microdroplet radii spanning ~10 to 30 μm are produced from the same droplet dispenser. These non-standard waveforms do not sacrifice the reproducibility of microdroplet generation with <1% size variation. Tuning the single squarewave pulsewidths induces predictable changes in the microdroplet radius with steps on the order of tens of nanometers are detectable. With finer voltage adjustments the microdroplet size is essentially tunable. These results confirm the extremely high stability and reproducibility of on-demand microdroplet generation and that precise size control is possible, rendering them suitable platforms for many applications in fundamental and applied research in areas including mass spectrometry, aerosol investigations and liquid-phase chemistry.3

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Microdroplet generation in gaseous and liquid environments

Cited by 35 publications

References 100 publications

Parameters affecting the shape of a hydrodynamically focused stream

Parameters affecting the shape of a hydrodynamically focused stream

Alternating Force Based Drop-on-Demand Microdroplet Formation and Three-Dimensional Deposition

Drop-on-demand microdroplet generation: a very stable platform for single-droplet experimentation

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