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Research: Complex Fluids and Flows
Our group explores fundamental problems in physico-chemical hydrodynamics. We are interested in the interrelation of processes at the nano-scale (e.g., fluctuations in membrane shape or composition), micro-scale (e.g., droplet/red cell deformation, lipid sorting), and macro-scale (e.g, emulsion/blood rheology). The research outcomes will aid the rational design of soft-materials with tunable microstructure and properties, and advance biomedical technologies that involve cell manipulation with external forces. Two main directions define our current research efforts:
Non-equilibrium complex interfaces
The lipid bilayer that encapsulates cells and cellular organelles is a dynamic environment, which modulates the biochemical function of the embedded proteins. We investigate the transport of exogenous molecules and particles into the cell through pores in the cell membrane created by electric pulses.
Flow and rheology of suspensions of deformable particles
Non-Newtonian features such as shear-rate dependent suspension
viscosity originate from flow-induced distortion of particle. shape and
orientation. We study the coupling between particle dynamics and
physico-chemical processes at the particle interface, e.g., surfactant or
Electrohydrodynamics of viscous drops
A classic result due to G.I.Taylor is that a drop placed in a uniform electric field becomes a prolate or oblate spheroid, which is axisymmetrically aligned with the applied field. We study the stability of drops in electric fields, particular the transition to obliquely orientation and fluid rotation. Our experiments reveal novel unsteady drop behaviors such as tumbling, oscillations and chaotic dynamics even under creeping flow conditions. Videos below: silicone oil in castor oil, (left) viscosity ratio=1, electric field strength=10.2kV/cm, radius=1.8mm, (center) viscosity ratio=4, electric field strength=9.2kV/cm, radius=1.8mm, (right) viscosity ratio=14, electric field strength=9.2kV/cm, radius=3.45mm.
Looking for a PhD or post-doc position?
Positions open as funding becomes available. Applications are welcomed from motivated students with strong background in physical chemistry, fluid mechanics, applied math, biophysics.
It is essential that the candidates for PhD, post-doctoral, and visiting researcher positions clearly elaborate on how their experience and future plans fit the activities of my group. I will not respond to mass-mail inquiries with generic content.
Please note that I DO NOT take summer interns.
Are you a pre-college student?
Brown has a long history of engagement with Providence area schools. Check the website of the Office of Education Outreach to find out more about the many exciting programs, especially in math and science!
Research Themes >