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Center for Nonlinear Studies |
Microfluidic devices manufactured from soft polymeric materials have emerged as a paradigm for cheap, disposable, and easy-to-prototype fluidic platforms for integrating chemical and biological assays and analyses. It is now understood that the interplay between the flow forces and the inherently compliant conduits within such devices requires careful consideration. At the same time, the mechanical compliance of these devices enables new approaches to "reconfigurable" microfluidic platforms for microrheometry, sieving of micro- and nano-particles, and development of biomimetic organs-on-a-chip, as well as new modalities of micromixing. In this talk, I will discuss our research program on the basic laws of soft hydraulics. Starting with steady flow through a rectangular microchannel, I will show how a complete understanding of the flow and deformation can be developed from scratch, rationalizing previous experiments. Next, I will show how our approach can be extended to capture non-Newtonian rheology and different conduit geometries' mechanical responses, leading to new experimental collaborations on shear-thinning fluids and Boger fluids in weakly viscoelastic flows. Next, I will describe how our theoretical building blocks can be used to piece together a theory for oscillatory flows through deformable microchannels, demonstrating a novel "elastoinertial" rectification mechanism (a type of self-induced streaming) in these flows. Time permitting, I will explain how our basic laws of soft hydraulics can enable a new understanding of why laminar flows in compliant microchannels become unstable at a low Reynolds number of 200 to 300 (instead of 2000 to 3000!).
Host: Avadh Saxena (T-4)