Themed collection Molecular and Ion Flows through Angstrom-scale Channels Faraday Discussion

Angstrom-scale fluidics reveals behaviors that defy universal laws, from anomalous dielectric effects to memristive transport. This breakdown of universality is not a limitation but an asset to enable new functionalities.

We introduce tubular response functions – a generalisation of surface response functions that captures how nanotubes with arbitrary electronic properties screen Coulomb interactions.

The controlled delivery of ions and molecules with sub-nanomolar accuracy holds significant potential. Here, the integration of photothermal o-CNT with V₂O₅ nanosheets to fabricate fluidic devices with precise ion and molecular release is shown.

Water kinetics in graphene oxide membranes reveal the 2D Maxwell–Stefan diffusion coefficient and the tortuosity of transport pathways underlying the ultrafast transport.

Herein we present an iontronic memristor using funnel-shaped Ångström channels, exhibiting behavior that differs from conventional conical nanochannel systems.

Comparison of ionic correlation maps computed with stochastic density field theory (left) and simulations (right).

We observed that when fluidic devices such as nanoporous membranes are measured with Ag/AgCl electrodes, pinched hysteresis in current–voltage (I–V) loops can be generated even when there is no intrinsic ionic memory behaviour.

Differences in surface charge determine distinct ion transport mechanisms in carbon and boron nitride nanotube porins.

Carbonate/bicarbonate speciation in water influences interactions between negatively charged surfaces, leading to variations in effective surface charge, screening length and hydration forces, highlighting the importance of chemical equilibria.

Our results uncover a voltage-regulated shift of kinetic control: at low polarization, the charging time is limited mainly by geometric confinement, whereas at high polarization, the relaxation becomes dictated by the applied voltage itself.

Position- and time-resolved X-ray transmission and small-angle X-ray scattering are used to map out ion transport and nanoscale ion arrangement in an in-plane carbon-based supercapacitor working electrode with 1 M RbBr aqueous electrolyte.

Cation–anion pairing promotes co-ion entry into Å-scale charged graphene nanoslits. Large clusters diffuse faster than expected and have size-dependent charge asymmetry, preferring single-body cations and negative many-body clusters.

Ionic memory vanishes in neat ionic liquid but reappears when solvent tuning or boundary asymmetry enables multiple conductance states under nanoconfinement.

Electric field driven alignment of confined water dipoles produces memristive ion transport with hysteresis and negative differential resistance. This coupling establishes a novel mechanism for neuromorphic functionality in nanofluidic systems.

Pictorial representation of how hydronium is able to retain its bulk-like hydrogen bonding structure under confinement between hexagonal boron nitride sheets, while hydroxide remains under coordinated.

Silicon nitride nanopores containing a DNA modified gold layer exhibit salt concentration and pore diameter dependent rectification and memristive properties.

We report a flexo-ionic effect in which bending or flexing GO membranes generates ionic potentials, arising from strain gradient-induced dynamic ionic streaming potentials in humid 2D nanofluidic channels.

Blocker induced non-linearity and emergent memristance in open pores.

We report a photoswitchable azobenzene-based channel that envelops a coherent water wire and efficiently regulates water and proton transport across lipid bilayers using light as an external trigger.

We propose a pathway toward iontronic circuits that can address established time series benchmark tasks, enabling performance comparisons and highlighting possible application domains for efficient real-time time series processing.

We investigate the evolution of ion selectivity in graphite nanochannels from dilute to water-in-salt regimes. Results show that the preferential adsorption of anions (TFSI⁻ and Cl⁻) is a low-concentration phenomenon that weakens with increasing molality.

We show that ion uptake and selectivity of functionalized molybdenum disulfide channels in a dimethylformamide–water solvent system are governed by the interplay of binding-site deprotonation and dielectric effects.

We use machine-learning molecular dynamics with first-principles accuracy to probe water at graphene surfaces across slit widths ranging from the open-interface limit to angstrom-scale confinement.