Characterization of pressure-driven water flows in nanofluidic channels by mass flowmetry

Abstract

With developments in analytical devices promoted by nanofluidics, estimation of the flow rate in a nanochannel has become important to calculate volumes of samples and reagents in chemical processing. However, measurement of the flow rate in nanospaces remains challenging. In the present study, a mass flowmetry system was developed, and the flow rate of water by pressure-driven flow in a fused-silica nanochannel was successfully measured in picoliters per second. We revealed that the water flow rate is dependent on the viscosity significantly increased in a square nanochannel with 10² nm width and depth (3.6 times higher than the bulk viscosity for a representative channel size of 190 nm) and slightly increased in a plate nanochannel with micrometer-scale width and 10² nm depth (1.3 times higher for that of 234 nm), because of dominant surface effects. The developed method and results obtained will greatly contribute to nanofluidics and other related fields.

Keywords: Flow rate; Nanochannel; Nanofluidics; Pressure-driven flow; Water.