Dynamically Modulating Gating Process of Nanoporous Membrane at Sub-2 Nm Scale

Gating properties of nanochannels, as a key nanofluidic behavior, holds huge applications in sensing, mass transportation and separation. It has been widely studied the terminal “open” and “close” states in response to changes of environments, for prepared nanochannels. Yet to date, it remains great challenge to control the dynamic gating process. Here in this manuscript, we modulate the dynamically electric gating process in polypyrrole (PPy)-based nanoporous membranes system at sub-2 nm speed. The nano-confinement environment renders the polymer chain with excellent electrochemical property and the polymer film swells or contracts in a controlled speed accompanied by a reversible counter-ion uptake or expulsion. With this switching process, the thickness of the polymer changes by 83%, resulting a fully closed gating state. Besides, we directly observe the successive polymer chain variation at nanoscale (ca. 10 nm) by the AFM topography in situ . This small operation voltages and ultra-high strain scope, along with biocompatible materials, make this design promising for smart nanorobot and wearable applications.