Microscale tipstreaming in a microfluidic flow focusing device

Anna, Shelley L.; Mayer, Hans C.

doi:10.1063/1.2397023

Cited by 345 publications

(357 citation statements)

References 52 publications

(74 reference statements)

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“…Droplets in Figure 3c are formed in the geometry-controlled regime, because the shear stress exerted by the continuous phase is small compared to interfacial stress. 32 Under this regime, droplets grow in the collection tube until they occupy almost the entire cross section. To maintain the applied flow rate, a higher pressure is needed in the continuous phase stream in order to drive flow through a narrow gap between the tube wall and the droplet interface.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Emulsion Templating of Poly(lactic acid) Particles: Droplet Formation Behavior

et al. 2012

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Monodisperse poly(DL-lactic acid) (PLA) particles of diameters between 11 and 121 μm were fabricated in flow focusing glass microcapillary devices by evaporation of dichloromethane (DCM) from emulsion droplets at room temperature. The dispersed phase was 5% (w/w) PLA in DCM containing 0.1−2 mM Nile Red and the continuous phase was 5% (w/w) poly(vinyl alcohol) in reverse osmosis water. Particle diameter was 2.7 times smaller than the diameter of the emulsion droplet template, indicating very low particle porosity. Monodisperse droplets have only been produced under dripping regime using a wide range of dispersed phase flow rates (0.002−7.2 cm 3 ·h −1 ), continuous phase flow rates (0.3− 30 cm 3 ·h −1 ), and orifice diameters (50−237 μm). In the dripping regime, the ratio of droplet diameter to orifice diameter was inversely proportional to the 0.39 power of the ratio of the continuous phase flow rate to dispersed phase flow rate. Highly uniform droplets with a coefficient of variation (CV) below 2% and a ratio of the droplet diameter to orifice diameter of 0.5−1 were obtained at flow rate ratios of 4−25. Under jetting regime, polydisperse droplets (CV > 6%) were formed by detachment from relatively long jets (between 4 and 10 times longer than droplet diameter) and a ratio of the droplet size to orifice size of 2−5.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Emulsion Templating of Poly(lactic acid) Particles: Droplet Formation Behavior

et al. 2012

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“…This transition has been studied extensively. 17 Within the jetting regime droplet generation does no longer occur at the flow-focusing region, but the jet breaks up further downstream due to the Rayleigh-Plateau instability. 18 We built a microfluidic device exhibiting a wide cavity after the flow-focussing region and modified the microchannel with a PAH-PSS-PAH-PSS PEM.…”

Section: High-throughput Production Of O/w Microdropletsmentioning

confidence: 99%

Hydrophilic PDMS microchannels for high-throughput formation of oil-in-water microdroplets and water-in-oil-in-water double emulsions

et al. 2010

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Here we present a novel surface modification method based on the sequential layer-by-layer deposition of polyelectrolytes yielding hydrophilic microchannels in PDMS-based microfluidic devices. The coatings are long-term stable and allow for the generation of monodisperse oil-in-water microdroplets even several months after the channel surface treatment. Due to the robustness of the polyelectrolyte multilayers ultra-high flow rates can be applied, making high-throughput droplet formation in the jetting mode possible. Furthermore, we successfully used our method to selectively modify the surface properties in certain areas of assembled microchannels. The resulting partially hydrophilic, partially hydrophobic microfluidic devices allow for the production of monodisperse water-in-oil-in-water double emulsions.

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“…This is however, not a general break-up mechanism and can mostly be attributed to the presence of impurities or a nonuniform surfactant distribution along the drop surface (14,15). Other break-up mechanisms have been described in literature, for instance when dealing with viscoelastic components (16,17) or when using microfluidic devices in which confinement effects become important (18,19). Here, however, we focus on bulk behavior of systems with Newtonian components.…”

Section: Ispersing One Fluid In a Second Immiscible Liquid Ismentioning

confidence: 99%

Single Droplet Break-up in Controlled Mixed Flows

Boonen

Puyvelde

Moldenaers

2010

ACS Appl. Mater. Interfaces

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In this work, the break-up dynamics of a single, Newtonian droplet dispersed in an immiscible Newtonian matrix undergoing a controlled mixture of shear and extensional flow is investigated using a homemade eccentric cylinder device. Hereto, different representative supercritical flows with varying shear/elongation balance have been applied. The effect of viscosity ratio is explored using droplets with a viscosity ratio of 0.1 and 1.3, respectively. In all cases, break-up is observed to proceed through an "end-pinching" mechanism. The experimentally obtained break-up times have been compared with scaling relations known from literature for simple shear and purely extensional flow. It is found that the global break-up dynamics is still shear dominated, even for conditions where the elongational contribution comprises a substantial amount (up to 30% on average) of the mixed flow.

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Microscale tipstreaming in a microfluidic flow focusing device

Cited by 345 publications

References 52 publications

Emulsion Templating of Poly(lactic acid) Particles: Droplet Formation Behavior

Emulsion Templating of Poly(lactic acid) Particles: Droplet Formation Behavior

Hydrophilic PDMS microchannels for high-throughput formation of oil-in-water microdroplets and water-in-oil-in-water double emulsions

Single Droplet Break-up in Controlled Mixed Flows

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