Electrical Field Regulation of Ion Transport in Polyethylene Terephthalate Nanochannels

Abstract

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.

Ion Selective Nanochannels: From Critical Principles to Sensing and Biosensing Applications

“…[143] Various parameters such as surface charge distribution, electrical double layer properties, surface functional groups, surface modification of nanochannel/nanopore, electrolyte concen tration, electrolyte pH, size of nanopore/nanochannels, exter nally applied bias potential, ion concentration polarization, and geometry of nanodevice can affect the ICR in nanobased devices. [62,64,101,148,[153][154][155][156][157][158] Asymmetric ion distributions along a nanochannel can generate ICR. Some parts of the nanochannel have a positively charged surface in aqueous solu tions in diodelike nanochannels, while the other parts are nega tively charged.…”

“…Although the monovalent ion concentration had a slight influence on polarity changes of conical PET nanochannels, a low concentration of trivalent cations (e.g., Cr 3+ and Fe 3+ ) and high concentration of divalent Mg 2+ ions reversed the surface of negatively charged PET. [101] Yang and Hu et al reported the coupled photoelectricionic transportation phenomenon through lamellar nanochannels of GO membrane. Figure 4 schematically demonstrates that the local light irradiation onto the confined layered GO in an electrochemical cell generated a net ionic flow through nanochannels (Figure 4a,b).…”

Rational ion transport management mediated through membrane structures

“…First, representative 1D nanochannel-structured organic membranes with various geometrical parameters include PET, polyimide (PI), polycarbonate (PC), short cyclodextrin nanotubes (CDNTs), and covalent organic frameworks (COFs) are discussed. PET is usually used to prepare symmetric (e.g., cylindrical [93] and cigar-shaped [94][95][96] ) and asymmetric (e.g., bullet-, [83] funnel-, [85,97] hourglass-, [75,98] and coneshaped [24,79,[99][100][101][102][103] ) nanochannels. For instance, PET membranes with cylindrical nanochannels can provide pathways for proton transport across a transmembrane concentration gradient.…”

Improved Rectification and Osmotic Power in Polyelectrolyte-Filled Mesopores

“…For example, the diode-like ion current rectification (ICR) behavior, which assures ions preferentially transporting in one direction and hence amplifies ionic current, can be observed when the symmetry of ionic concentration profiles along the axis of a nanopore is broken [ 18 , 19 ]. Considerable experimental [ 20 , 21 , 22 ] and theoretical [ 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ] efforts have been made on ICR in nanofluidics and all these studies concluded that the ICR property only can emerge in case the pore size is comparable to the EDL thickness.…”