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. Although all of these diverse applications are done in an aqueous environment, little is known about fluid flow and its coupling with ion transport properties. Understanding the physics underlying ion transport through nano-sized pores allows better design of porous membrane materials and nanopore sensors.

 

I will 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 are able to induce two separate phenomena.  First, due to a low hydraulic resistance at the mouth of the pore, advective ion transport dominates diffusive, causing nonlinear coupling of ion transport with the 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 or hBN, opening up pathways to probing ionic hydration layers and artificial mechanosensitive sensors.