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 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.

Performance tuning of microfluidic flow-focusing droplet generators

Lab on a Chip ◽  
2019 ◽  
Vol 19 (6) ◽  
pp. 1041-1053 ◽  
Author(s):  
Ali Lashkaripour ◽  
Christopher Rodriguez ◽  
Luis Ortiz ◽  
Douglas Densmore
Keyword(s):  
Droplet Size ◽  
Design Space ◽  
Performance Tuning ◽  
Generation Rate ◽  
Flow Focusing ◽  
Microfluidic Flow ◽  
Droplet Generators

We explored a large design space to identify the coarse/fine tuners in determining droplet size, generation rate, regime, and polydispersity.

scholarly journals A 3D hydrodynamic flow-focusing device for cell sorting

2021 ◽  
Vol 25 (3) ◽  
Author(s):  
Xiaofei Yuan ◽  
Andrew Glidle ◽  
Hitoshi Furusho ◽  
Huabing Yin
Keyword(s):  
Cell Sorting ◽  
Control Strategies ◽  
Three Dimensional ◽  
Hydrodynamic Flow ◽  
Proof Of Concept ◽  
Flow Focusing ◽  
Hydrodynamic Focusing ◽  
Cell Handling ◽  
Fluid Flow Control ◽  
High Degree

AbstractOptical-based microfluidic cell sorting has become increasingly attractive for applications in life and environmental sciences due to its ability of sophisticated cell handling in flow. The majority of these microfluidic cell sorting devices employ two-dimensional fluid flow control strategies, which lack the ability to manipulate the position of cells arbitrarily for precise optical detection, therefore resulting in reduced sorting accuracy and purity. Although three-dimensional (3D) hydrodynamic devices have better flow-focusing characteristics, most lack the flexibility to arbitrarily position the sample flow in each direction. Thus, there have been very few studies using 3D hydrodynamic flow focusing for sorting. Herein, we designed a 3D hydrodynamic focusing sorting platform based on independent sheath flow-focusing and pressure-actuated switching. This design offers many advantages in terms of reliable acquisition of weak Raman signals due to the ability to precisely control the speed and position of samples in 3D. With a proof-of-concept demonstration, we show this 3D hydrodynamic focusing-based sorting device has the potential to reach a high degree of accuracy for Raman activated sorting.

scholarly journals Subthreshold laser jetting via flow-focusing in laser-induced forward transfer

2018 ◽  
Vol 3 (8) ◽  
Author(s):  
Emre Turkoz ◽  
SeungYeon Kang ◽  
Luc Deike ◽  
Craig B. Arnold
Keyword(s):  
Flow Focusing ◽  
Forward Transfer ◽  
Subthreshold Laser

scholarly journals Study on External Gas-Assisted Mold Temperature Control with the Assistance of a Flow Focusing Device in the Injection Molding Process

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 965 ◽  
Author(s):  
Nguyen Truong Giang ◽  
Pham Son Minh ◽  
Tran Anh Son ◽  
Tran Minh The Uyen ◽  
Thanh-Hai Nguyen ◽  
...  
Keyword(s):  
Injection Molding ◽  
Temperature Control ◽  
Mold Temperature ◽  
Injection Molding Process ◽  
Melt Flow ◽  
Flow Focusing ◽  
Molding Process ◽  
Heating Efficiency ◽  
Flow Length ◽  
Insert Plate

In the injection molding field, the flow of plastic material is one of the most important issues, especially regarding the ability of melted plastic to fill the thin walls of products. To improve the melt flow length, a high mold temperature was applied with pre-heating of the cavity surface. In this paper, we present our research on the injection molding process with pre-heating by external gas-assisted mold temperature control. After this, we observed an improvement in the melt flow length into thin-walled products due to the high mold temperature during the filling step. In addition, to develop the heating efficiency, a flow focusing device (FFD) was applied and verified. The simulations and experiments were carried out within an air temperature of 400 °C and heating time of 20 s to investigate a flow focusing device to assist with external gas-assisted mold temperature control (Ex-GMTC), with the application of various FFD types for the temperature distribution of the insert plate. The heating process was applied for a simple insert model with dimensions of 50 mm × 50 mm × 2 mm, in order to verify the influence of the FFD geometry on the heating result. After that, Ex-GMTC with the assistance of FFD was carried out for a mold-reading process, and the FFD influence was estimated by the mold heating result and the improvement of the melt flow length using acrylonitrile butadiene styrene (ABS). The results show that the air sprue gap (h) significantly affects the temperature of the insert and an air sprue gap of 3 mm gives the best heating rate, with the highest temperature being 321.2 °C. Likewise, the actual results show that the height of the flow focusing device (V) also influences the temperature of the insert plate and that a 5 mm high FFD gives the best results with a maximum temperature of 332.3 °C. Moreover, the heating efficiency when using FFD is always higher than without FFD. After examining the effect of FFD, its application was considered, in order to improve the melt flow length in injection molding, which increased from 38.6 to 170 mm, while the balance of the melt filling was also clearly improved.

scholarly journals Negative Pressure Provides Simple and Stable Droplet Generation in a Flow-Focusing Microfluidic Device

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 662
Author(s):  
Nikita A. Filatov ◽  
Anatoly A. Evstrapov ◽  
Anton S. Bukatin
Keyword(s):  
Microfluidic Device ◽  
Negative Pressure ◽  
Low Cost ◽  
Control Valve ◽  
Droplet Microfluidics ◽  
Droplet Generation ◽  
Electric Signal ◽  
Absolute Pressure ◽  
Flow Focusing ◽  
Wide Range

Droplet microfluidics is an extremely useful and powerful tool for industrial, environmental, and biotechnological applications, due to advantages such as the small volume of reagents required, ultrahigh-throughput, precise control, and independent manipulations of each droplet. For the generation of monodisperse water-in-oil droplets, usually T-junction and flow-focusing microfluidic devices connected to syringe pumps or pressure controllers are used. Here, we investigated droplet-generation regimes in a flow-focusing microfluidic device induced by the negative pressure in the outlet reservoir, generated by a low-cost mini diaphragm vacuum pump. During the study, we compared two ways of adjusting the negative pressure using a compact electro-pneumatic regulator and a manual airflow control valve. The results showed that both types of regulators are suitable for the stable generation of monodisperse droplets for at least 4 h, with variations in diameter less than 1 µm. Droplet diameters at high levels of negative pressure were mainly determined by the hydrodynamic resistances of the inlet microchannels, although the absolute pressure value defined the generation frequency; however, the electro-pneumatic regulator is preferable and convenient for the accurate control of the pressure by an external electric signal, providing more stable pressure, and a wide range of droplet diameters and generation frequencies. The method of droplet generation suggested here is a simple, stable, reliable, and portable way of high-throughput production of relatively large volumes of monodisperse emulsions for biomedical applications.

Sign in / Sign up

Export Citation Format

Share Document