Evaluation of Fluid Flow Through Micromachined Nanoporous Membranes using a Custom-Built Automated Testing and Data Acquisition System

Evaluation of fluid flow through micromachined nanoporous membranes using a custom-built automated system designed specifically for nanofluidic applications is presented. The nanoporous membranes are fabricated by a process that combines Si micromachining with sacrificial etching of a nanoscale oxide film. The automated system consists of a precision electronic mass balance, a differential pressure transducer, and a laptop computer with a data acquisition and control card configured to collect data from the balance and differential pressure transducer. Performance of the system was first evaluated for microfluidic applications by measuring the flow of deionized (DI) water through narrow diameter (133 μm) tubing and comparing the measured values to those calculated using theoretical considerations. The system was then used to measure flow rates of DI water through a micromachined nanoporous silicon membrane. The data shows that the system performed within the limits of experimental uncertainty.