Nanofluidic Pulser Based on Polymer Conical Nanopores

The study of voltage-dependent ion current fluctuation phenomena in synthetic nanopores is important as it is helpful to investigate the mechanism of mass transport in nanoscale systems, which have similarities with natural ion channels in the biological cell membrane. Moreover, we could fabricate some high-performance nanofluidic devices through clearly understanding ion current fluctuation behavior. In this paper, we report a nanofluidic pulser induced by formation and dissolution of weakly soluble salts in conical nanopores. The current fluctuation signals are easily controllable in 1 M KCl electrolyte. Amplitude, frequency, and waveform of ion fluctuation current of the nanofluidic pulser could be controlled by changing the applied negative voltage, and the time ratio of pore opening/dosing could be simply manipulated by the concentration of the bivalent cation. A high-quality square wave of ion current signal is found, especially when the negative voltage is below 300 mV. Additionally, we developed a new model about the formation and dissolution process of precipitation. Our work is helpful for the design of nanoscale ion current waveform generators in the future.