  When channels were scaled down to the size of hydrated ions, ionic Coulomb
blockade was discovered. However, the experimental CB phenomenon was rarely
reported since Feng et.al., discovered in MoS2 nanopore. By using latent-track
membranes with diameter of 0.6 nm, we found the channels are nearly
non-conductive in small voltage due to the blockade of cations bound at
surface, however turns to be conductive as rising of voltage due to releasing
of bound ions, which differs from the mechanisms in MoS2 nanopore. By Kramers'
escape framework, we rationalized an analytical equation to fit experimental
results, uncovering new fundamental insights of ion transport in the smallest
channels.
