Pressure-Induced Enlargement and Ionic Current Rectification in Symmetric Nanopores

Nanopores in solid state membranes are a tool able to probe nanofluidic phenomena or can act as a single molecular sensor. They also have diverse applications in filtration, desalination, or osmotic power generation. Many of these applications involve chemical, or hydrostatic pressure differences which act on both the supporting membrane, and can influence the ion transport through the pore. We demonstrate an approach using hydraulic pressure coupled with alternating current which is used to probe small differences in ion transport characteristics of nanopores. Through hydraulic pressure differences between the sides of the membrane we measure two separate phenomena. First, due to a low hydraulic resistance at the mouth of the pore, advective ion transport dominates diffusive, causing ionic current rectification due to applied pressure. Secondly, we demonstrate that blistering of the membrane under pressure induces enlargement of the pore diameter, and is a direct measure of the strain at the pore. This allows controlled application of in-situ strain on nanopores in 2D materials like MoS2, opening up the pathways to artificial mechanosensitive sensors.