scholarly journals Customized Design of Scalable Microfluidic Droplet Generators Using Step‐Emulsification Methods

2019 ◽  
Vol 42 (10) ◽  
pp. 2195-2201 ◽  
Author(s):  
Angelika Eberhardt ◽  
Dušan Bošković ◽  
Stefan Loebbecke ◽  
Slobodan Panić ◽  
Yannik Winter
Keyword(s):  
Droplet Generators

scholarly journals A Liquid-Metal-Based Dielectrophoretic Microdroplet Generator

Micromachines ◽  
2019 ◽  
Vol 10 (11) ◽  
pp. 769 ◽  
Author(s):  
Wang ◽  
Zhang ◽  
Gao ◽  
Wang ◽  
Deng ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Electric Field ◽  
Numerical Simulations ◽  
Parametric Study ◽  
Microfluidic Channel ◽  
Droplet Generator ◽  
Metal Electrodes ◽  
Droplet Generators

This paper proposes a novel microdroplet generator based on the dielectrophoretic (DEP) force. Unlike the conventional continuous microfluidic droplet generator, this droplet generator is more like “invisible electric scissors”. It can cut the droplet off from the fluid matrix and modify droplets’ length precisely by controlling the electrodes’ length and position. These electrodes are made of liquid metal by injection. By applying a certain voltage on the liquid-metal electrodes, the electrodes generate an uneven electric field inside the main microfluidic channel. Then, the uneven electric field generates DEP force inside the fluid. The DEP force shears off part from the main matrix, in order to generate droplets. To reveal the mechanism, numerical simulations were performed to analyze the DEP force. A detailed experimental parametric study was also performed. Unlike the traditional droplet generators, the main separating force of this work is DEP force only, which can produce one droplet at a time in a more precise way.

scholarly journals Microfluidic droplet generation based on non-embedded co-flow-focusing using 3D printed nozzle

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Adrien Dewandre ◽  
Javier Rivero-Rodriguez ◽  
Youen Vitry ◽  
Benjamin Sobac ◽  
Benoit Scheid
Keyword(s):  
Stokes Equations ◽  
Axisymmetric Flow ◽  
Droplet Generation ◽  
Droplet Radius ◽  
Planar Geometry ◽  
Flow Focusing ◽  
Glass Capillary ◽  
New Device ◽  
3D Printed ◽  
Droplet Generators

AbstractMost commercial microfluidic droplet generators rely on the planar flow-focusing configuration implemented in polymer or glass chips. The planar geometry, however, suffers from many limitations and drawbacks, such as the need of specific coatings or the use of dedicated surfactants, depending on the fluids in play. On the contrary, and thanks to their axisymmetric geometry, glass capillary-based droplet generators are a priori not fluid-dependent. Nevertheless, they have never reached the market because their assembly requires fastidious and not scalable fabrication techniques. Here we present a new device, called Raydrop, based on the alignment of two capillaries immersed in a pressurized chamber containing the continuous phase. The dispersed phase exits one of the capillaries through a 3D-printed nozzle placed in front of the extraction capillary for collecting the droplets. This non-embedded implementation of an axisymmetric flow-focusing is referred to non-embedded co-flow-focusing configuration. Experimental results demonstrate the universality of the device in terms of the variety of fluids that can be emulsified, as well as the range of droplet radii that can be obtained, without neither the need of surfactant nor coating. Additionally, numerical computations of the Navier-Stokes equations based on the quasi-steadiness assumption allow to provide an explanation to the underlying mechanism behind the drop formation and the mechanism of the dripping to jetting transition. Excellent predictions were also obtained for the droplet radius, as well as for the dripping-jetting transition, when varying the geometrical and fluid parameters, showing the ability of this configuration to enventually enhance the dripping regime. The monodispersity ensured by the dripping regime, the robustness of the fabrication technique, the optimization capabilities from the numerical modelling and the universality of the configuration confer to the Raydrop technology a very high potential in the race towards high-throughput droplet generation processes.

Understanding Fundamental Physics of Aqueous Droplet Generation Mechanisms in the Aqueous Environment

2017 ◽  
Author(s):  
Mohammad Mastiani ◽  
Seokju Seo ◽  
Sofia Melgar Jimenez ◽  
Nick Petrozzi ◽  
Myeongsub (Mike) Kim
Keyword(s):  
Droplet Formation ◽  
Phase System ◽  
Aqueous Environment ◽  
Flow Focusing ◽  
Two Phase ◽  
Droplet Sizes ◽  
Generation Mechanisms ◽  
Hydrodynamic Behaviors ◽  
Aqueous Droplet ◽  
Droplet Generators

Recent advent of Aqueous-Two-Phase-System (ATPS), more biologically friendly compared to conventional oil-water systems, has shown great potential to rapidly generate aqueous droplets without tedious post-processing. However, understanding of underlying physics of droplet formation in ATPS is still in its infancy. In this paper, we investigate hydrodynamic behaviors and mechanisms of all-aqueous droplet formation in two flow-focusing droplet generators. Two incompatible polymers namely polyethylene glycol (PEG) and dextran (DEX) are mixed in water to make ATPS. The influence of inlet pressures and flow-focusing configurations on droplet sizes, and thread breakup length is studied. Flow regime mapping for two different configurations of droplet generators possessing junction angles of 30° and 90° is also obtained. The results show that droplet size is very susceptible to the junction angle while inlet pressures of the PEG and DEX flows readily control four main flow regimes including back flow, dripping, jetting and stratified.

Simultaneous generation of droplets with different dimensions in parallel integrated microfluidic droplet generators

Soft Matter ◽  
2008 ◽  
Vol 4 (2) ◽  
pp. 258-262 ◽  
Author(s):  
Wei Li ◽  
Edmond W. K. Young ◽  
Minseok Seo ◽  
Zhihong Nie ◽  
Piotr Garstecki ◽  
...  
Keyword(s):  
Simultaneous Generation ◽  
Different Dimensions ◽  
Droplet Generators

Microfluidic consecutive flow-focusing droplet generators

Soft Matter ◽  
2007 ◽  
Vol 3 (8) ◽  
pp. 986 ◽  
Author(s):  
Minseok Seo ◽  
Chantal Paquet ◽  
Zhihong Nie ◽  
Shengqing Xu ◽  
Eugenia Kumacheva
Keyword(s):  
Flow Focusing ◽  
Droplet Generators

scholarly journals Lithium Niobate Micromachining for the Fabrication of Microfluidic Droplet Generators

Micromachines ◽  
2017 ◽  
Vol 8 (6) ◽  
pp. 185 ◽  
Author(s):  
Giacomo Bettella ◽  
Gianluca Pozza ◽  
Sebastian Kroesen ◽  
Riccardo Zamboni ◽  
Enrico Baggio ◽  
...  
Keyword(s):  
Lithium Niobate ◽  
Droplet Generators

scholarly journals Microfluidic Droplet-Storage Array

Micromachines ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 608 ◽  
Author(s):  
Hoon Suk Rho ◽  
Han Gardeniers
Keyword(s):  
Fluid Flow ◽  
Microfluidic Chip ◽  
Continuous Operation ◽  
Operating Conditions ◽  
Storage Unit ◽  
Carrier Fluid ◽  
Complex Chemical ◽  
Precise Control ◽  
Storage Units ◽  
Droplet Generators

A microfluidic droplet-storage array that is capable of the continuous operation of droplet formation, storing, repositioning, retrieving, injecting and restoring is demonstrated. The microfluidic chip comprised four valve-assisted droplet generators and a 3 × 16 droplet-storage array. The integrated pneumatically actuated microvalves enable the precise control of aqueous phase dispensing, as well as carrier fluid flow path and direction for flexible manipulating water-in-oil droplets in the chip. The size of droplets formed by the valve-assisted droplet generators was validated under various operating conditions such as pressures for introducing solutions and dispensing time. In addition, flexible droplet addressing in the storage array was demonstrated by storing droplets with various numbers and compositions in different storage units as well as rearranging their stored positions. Moreover, serial injections of new droplets into a retrieved droplet from a storage unit was performed to show the potential of the platform in sequential dosing on incubated droplet-based reactors at the desired timeline. The droplet-storage array with great freedom and flexibility in droplet handling could be applied for performing complex chemical and biologic reactions, especially in which incubation and dosing steps are necessary.

scholarly journals 3D printed fittings and fluidic modules for customizable droplet generators

RSC Advances ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 2822-2828 ◽  
Author(s):  
Sindhu Vijayan ◽  
Michinao Hashimoto
Keyword(s):  
Rapid Method ◽  
Simple Method ◽  
3D Printed ◽  
Droplet Generators

We developed a rapid method to prototype axisymmetric droplet generators using 3D printed fittings and commercially available components. This simple method allowed generating simple and complex emulsions of varying sizes and configurations.

Variation in polydispersity in pump- and pressure-driven micro-droplet generators

2015 ◽  
Vol 25 (11) ◽  
pp. 115015 ◽  
Author(s):  
Wen Zeng ◽  
Ian Jacobi ◽  
Songjing Li ◽  
Howard A Stone
Keyword(s):  
Droplet Generators ◽  
Pressure Driven
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