High Spatial and Temporal Resolution Velocimetry Measurements for Microfluidic Devices

Microscale and nanoscale fluid engineering is an emergent technology with applications in many areas including micro-gas turbine engines, space propulsion, biotechnology, and materials processing. Uncertainties in the near-wall velocity flow and in the exact nature of the fluid-solid boundary condition become particularly important for microengineering applications where careful control of flow rates versus applied pressures are required and where novel fluids and materials are used in new and more complex devices. To rectify this gap in understanding and predictive ability and address the immediate engineering need for diagnostic sensors, Physical Sciences Inc. (PSI) in collaboration with our academic research partner, Brown University, proposes to develop and demonstrate a system which will measure fluid velocities in near solid surfaces in microfluidic devices. The instrument combines Waveguided Evanescent field Fluorescence Microscopy (WEFM), high efficiency quantum dot fluorescence probes, and Particle Tracking Velocimetry (PTV) algorithms. In the proposed Phase II program, we will • Optimize the waveguide design for use in fluorescence microscopy • Improve the performance of the quantum dot probes • Perform novel velocimetry measurements in microfludic liquid flows • Extend this capability to gas-phase flows • Deliver an easily-transportable, robust, flexible, and automated instrument capable of nanometer scale flow characterization.