Time Dependent Gating in Nanochannels

Thumbnail Image



Journal Title

Journal ISSN

Volume Title


Research Projects

Organizational Units

Journal Issue


Nanofluidic field effect devices, geometrically analogous to semiconductor field effect transistors, feature a gate electrode embedded in the wall of the nanofluidic channel, electrically and fluidically isolated from the working fluid. The gate electrode generates local change in the surface charge of the nanochannel wall directly beneath the gate. The change in surface charge alters the electric field, likely extending throughout the depth of the nanochannels, allowing for the manipulation of the potential at the dielectric-electrolyte interface. This allows for active, tunable control of ionic transport through the nanochannel or nanopore. Control over ionic transport through nanofluidic devices is desired for water desalination, artificial ion channels, ion pumps, fluidic molecular circuits, ion separation, and biosensing. Till date, experiments have shown significant advances using DC excitation at the gate in these nanofluidic devices. Our work focuses on using an alternating current to generate the gate excitation; a rarely explored parameter in these devices. The experimental study was conducted with a nanofluidic field effect device filled with a pH 7 potassium chloride (KCl) electrolyte solution. Axial (applied across the nanochannels) and gate (applied to the gate electrode) voltages were applied to systematically explore the effect of the gate electrode on the ionic transport in the nanochannels as measured through the ionic current measured through the device. Both DC and root mean square (RMS) matched AC signals were applied to the gate electrode and compared the results were analyzed and compared for time averaged current and total change in the current or "current modulation" from the zero gate voltage case. In addition to the first demonstration of an AC signal used to drive ionic transport through a gated nanofluidic device, conclusions from this study revealed the AC signals showing an order of magnitude higher current modulation than in the DC case. The implications of this work would be the indication lower applied gate voltages to drive equivalent ionic transport in nanochannels with AC signals. This could allow water desalination systems based off this technology to remove ionic contaminates at lower voltages resulting in overall lower power consumption.


Poster Division: Engineering, Math, and Physical Sciences: 1st Place (The Ohio State University Edward F. Hayes Graduate Research Forum)


nanochannel, microfluidics, nanofluidics, AC