Field effect regulation of Donnan potential and electrokinetic flow in a functionalized soft nanochannel

Controlling charge properties and electrokinetic flow (EKF) in a nanochannel is essential for the development of next generation nanofluidics based biosensing devices. In this study, active control of the Donnan potential and EKF in a functionalized soft nanochannel, comprising a solid-state nanochannel functionalized with a polyelectrolyte (PE) brush layer, using a field effect transistor (FET) is theoretically investigated for the first time. Both the magnitude and sign of the Donnan potential in the functionalized soft nanochannel can be effectively regulated by the gate potential imposed on the FET and the salt concentration. In addition, the salt concentration dependence of the EKF velocity profiles inside and outside the PE brush layer of the functionalized soft nanochannel are distinctly different.