FIG. 2.

(a) Measured conductance of a single conic nanopore ion-track PET membrane, charge-free nanopipette, and patch pipette, normalized by the zero-voltage conductance of each experiment, as a function of voltage. A quadratic increase with respect to voltage is observed, in violation of Ohmic law with constant conductance. (b) Membrane, nanopipette, and patch pipette data collapsed by the scaling theory into a linear correlation with respect to a normalization factor that contains cone angle θ (2.6°, 2.5° and 4.5° degrees for polymer nanopore, nanopipettes, and patch pipette, respectively), k = 0.15 and 0.6 W m⁻¹ K⁻¹ for the PET membrane pore and the silica pipettes, coefficient of temperature-dependent electrical conductivity m, thermal conductivity outside the cone k, conductivity σ at indicated ionic strength at room temperature, and voltage V. Insets show cavitation in both the nanopore membrane and patch pipette at the corresponding voltages. Cavitating bubbles are first observed within the patch pipette at some distance from the tip, as shown in the second inset, but will eventually grow sufficiently to exit the pipette, as is observed at the membrane surface.