Rectified ion transport in nanochannels is the basis of ion channels in biological cells and has inspired emerging nanochannel applications in ion separation, Coulter counters, and biomolecule detection and nanochannel energy harvesters. In this work we fabricated a polyethylene terephthalate (PET) conical nanochannel using latent ion track etching technique and then systematically studied the ion transport and influence of cation species on the nanochannel surface with cyclic I-V measurement. We discovered the electrical regulation of the reversible and irreversible modification of the nanochannel transportation by bivalent and trivalent cations, revealing the existence of the switching threshold voltage which can control the current rectification in bivalent solution. The proposed mechanism of the transport state transition in the PET nanochannel mimics behaviors of voltage-gated biological ion channels. These findings provide new insight into the understanding of the ion channel signaling and translocation control of charged particles in nanochannel applications.
Keywords: charge inversion; electrical regulation; ion track; ion transportation; nanochannel.