The effect of an external gate potential control on the nanofluidic nanochannels was experimentally investigated in this work. Like in the field effect transistors (FET) in microelectronics, molecular transport in micro/nanofluidic channels can be controlled by applying external potentials on the wall of the fluidic channel. In nanofluidic devices, this type of control is expected to be more efficient due to its high surface to charge ratio. We focused on a nanofluidic concentrator to study this effect. We could increase or decrease the concentration rate of the device by increasing or decreasing the surface charge potential (-potential) on the walls of the nanochannels. An increased -potential enhances the electrokinetic effects caused by electrical double layer. Which in turn accelerates the creation of a charge polarization region and improves the concentration capabilities of the device. We also have demonstrated concentration polarization effect, caused by pressure-driven flow in the nanofluidic channel, and showed that this phenomena can also be modulated by changing the gate potential of the nanofluidic devices. The gate potential effect opens the door for closed-loop real-time control of nanofluidic concentrators.
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