(5av) Complex Flows of Complex Materials at the Micro- and Nano-Scale

Advancements in cutting-edge fields such as micro- and nano-fluidics, self assembly, cellular mechanics, and complex fluids, require a thorough knowledge of fluid mechanics and transport processes --- a traditional pillar of chemical engineering science. In this poster, I present selected vignettes from my research on fluid dynamics and transport at the micro- and nano-scale. More specifically, I will discuss the following: (i) a variety of problems concerning electrically driven, or electrokinetic, flows, including electro-osmosis over surfaces bearing nano-scale inhomogeneities [1], electrophoresis of "slippery" colloids [2], steric effects on electrophoresis, and voltage-gated nanochannels for sample preconcentration (ii) Active microrheology of complex microstructured fluids, as a means of inferring nonlinear rheological properties, such as micro-viscosity [3] and normal stress differences. Finally, I will outline directions for future research in these and other areas.

References:

[1] A. S. Khair and T. M. Squires, "Surprising consequences of ion conservation in electro-osmosis over a surface charge discontinuity," J. Fluid Mech. 615, 323-334 (2008).

[2] A. S. Khair and T. M. Squires, "The influence of hydrodynamic slip on the electrophoretic mobility of a spherical colloidal particle," Phys. Fluids 21, 042001 (2009).

[3] A. S. Khair and J. F. Brady "Single particle motion in colloidal dispersions: a simple model for active and nonlinear microrheology," J. Fluid Mech. 557, 73 (2006).

For further information please visit: http://engineering.ucsb.edu/~akhair/