Field Effect Control of Surface Charge Property and Electroosmotic Flow in Nanofluidics

The surface charge property of nanofluidic devices plays an essential role in electrokinetic transport of ions, fluids, and particles in them. The nanofluidic field effect transistor (FET), referring to a nanochannel embedded with an electrically controllable gate electrode, provides a simple way to rapidly regulate its surface charge property, which in turn controls the electrokinetic transport phenomena within the nanochannel. In this study, approximate analytical expressions are derived for the first time to estimate the surface-charge property and electroosmotic flow (EOF) in charge-regulated nanochannels tuned by the nanofluidic FET and are validated by comparing their predictions to the existing experimental data available from the literature. The control of the surface charge property as well as the EOF by the nanofluidic FET depends on the pH and ionic concentration of the aqueous solution.