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Research

Microfluidics is an emerging cross-disciplinary field that offers many opportunities for scientific and technological advancements.
The laboratory's research interests include the development and application of methods to produce and control soft and reactive interfaces at the microscale. To this end, various aspects of interfacial fluid dynamics and hydrodynamics are examined in silicon and glass microfluidic modules using high-speed imaging.

Investigations focus on the control of viscous and capillary instabilities of microflows in simple and complex geometries. Research areas span between advanced micro-fabrication techniques, multiphase flows, wetting dynamics, miscible flows, and the rheology of complex fluids.


Microfluidic Multiphase Flows
Multiphase flows are encountered in a wide range of applications including chemical, petroleum, and power generation industries. Miniaturization of fluidic devices makes it possible to control fluids streams, droplets, and bubbles in a way that is unprecedented.  The understanding of multiphase flow at the microscale not only provides fundamental scientific insights but also offers new functionalities for practical uses.

Miscible flows
The precise manipulation of miscible fluids with large viscosity contrast  flowing co-currently at the microscale is
an important challenge in science and engineering.
Passive and active methods are investigated to enhance mixing between laminar fluid streams. Examples of application include the enhancement of chemical reactions between widely disperates species, such as between viscous material, including complex fluids, and less viscous fluids, including solvent.
 
                         Heterogeneous viscous flow
Immisicible flows
Droplets and emulsions: Microfluidic systems provide the advantage of generating arrays of droplets and bubbles with a high degree of monodispersity. Droplets can be created one-by-one at the junction of cross-channels. We study the influence of flow geometries and fluid thermodynamical  properties on the collective behavior and the hydrodynamic coupling of droplets in the presence and in the absence of surfactant.

Droplets collective behavior
 
            Emulsion flow patterns
Bubbles and foams: The conditions for bubble formation, displacement, coalescence, packing, and separation from continuous phase are investigated with silicon and glass microchannels in the presence of surface modifications (hydrophilic and hydrophobic surfaces) as well as with the addition of particulates.

Flowing bubble partially drying microchannel walls
 
Transport of bubbles in square microchannels




Wetting and dewetting
The motion of a contact line (fluid/fluid/solid interface) often takes place on a non-ideal surface.
Surface modifications and patterning allow for manipulating advancing and receding contact line dynamics, which can be used to confine and displace minute amount of fluid on a surface.


Contact line  edge detection


Faceted drop growth on
periodically patterned surfaces


Spontaneous dewetting on a heterogeneous surface