Dynamic microscale flow patterning using chemical and electrical modulation of zeta potential

Abstract

The ability to move fluids at the microscale is at the core of many scientific and technological advancements, including genetic sequencing, ink-jet printing, singe cell analysis, tissue engineering and fuel cells. Despite its importance, microfluidic control remains highly limited, even primitive, using discrete channels and mechanical valves to manipulate fluids. One of the themes in my lab is leveraging the unique physicochemical processes at the microscale toward the creation of novel methods for manipulation of fluids and of elastic interfaces. Following a brief introduction to electroosmotic flows, I will present an analytical model and experimental demonstration for the use of non-uniform surface charge subjected on an electric field, to create desired flows at the microscale without the need for physical walls. I will demonstrate static implementations using chemical surface patterning, as well as dynamic zeta potential modification using field effect electrodes. Finally, I will demonstrate the use of spatial flow patterning as the basis for a new method for diffusion-based separation. Time permitting, I will also discuss our work on electro-viscous-elasticity - the interaction between such non- uniform electroosmotic flows and elastic surfaces, with the goal of realizing dynamically configurable microstructures.

MORAN BERCOVICI

Faculty of Mechanical Engineering, Technion – Israel Institute of Technology