Themed collection Water at interfaces

This Faraday Discussion explored the complexity of water at different interfaces. These summarizing remarks sketch the status of the field, highlight the progress that the community has made, and present eclectic examples of where more work needs to be done.

The investigation of alkali metal cations within the H-bonding network of water on graphite and graphene-Cu(111) surfaces reveals the high sensitivity of ion-ion interactions and ionic ordering to the surface hydrophobicity and hydrophilicity.

In this article we discuss current issues in the context of the four chosen subtopics for the meeting: dynamics and nano-rheology of interfacial water, electrified/charged aqueous interfaces, ice interfaces, and soft matter/water interfaces.

This study reports on the applicability of X-ray transmission, small- and wide-angle X-ray scattering and small-angle neutron scattering for investigating processes in the working electrode of an electric double-layer capacitor at different applied potentials.

We compute the Raman and IR spectra of water nanoconfined by graphene at ambient and extreme pressure–temperature conditions using ab initio simulations.

The structure of dissolved NaCl ions in an aqueous nanodroplet resembles the structure of a molten NaCl nanoparticle. With decreasing size, the similarity grows and the potential energy of NaCl in solution, the molten phase and the crystal phase converges.

The solute-size dependence of the osmotic second virial coefficient is calculated and the effect of the strength of solute–solvent attraction on the effective pair potential between solutes of varying size is examined.

We investigate the changes in enthalpy and configurational entropy under the insertion of an ammonium ion into ice. For a reasonable surface charge the most energetically stable configuration of ammonium in ice increases the configurational entropy.

CμMD simulations demonstrate the effect of applied surface charge and solution concentration on the structure and thermodynamic properties of ions and water in the electric double layer.

Binding site occupancy and the mechanism of K selectivity involve multiple K binding in multiple neighboring layers, or sites, of the K channel selectivity filter.

We predict the quantum vibrational spectra of complex aqueous interfaces. We learn potentials that encode the quantum nuclear effects and physics-based models of dielectric responses, reducing quantum dynamics to classical molecular dynamics.

We show how it is possible to design and fabricate self-propelling microswimmers based on Nafion, driven by ion-exchange, and fueled by innocuous salts.

Counterions in solution and within a lipid monolayer differently neutralise charge- and dipole-induced water orientation.

We study the effects of changing electrolyte concentration on interfacial potential profiles, specifically comparing the predictions of continuum-level theory and all-atom molecular dynamics simulation.

We study the influence of excess water on the phase transition of lipidic mesophases from the cubic to reverse hexagonal phase. Excess water permeates the interface and forms additional hydrogen bonds with lipids, accelerating the lipid dynamics.

This article introduces confined response functions, which provide a general framework for the Coulomb interactions of fluctuating matter in nanoscale confinement.

A machine-learning force field paves the way for the simulation of heterogeneous ice nucleation on microcline from first principles.

We investigate the extent to which the size of the critical nucleus and the rate at which it grows in thin films of water are affected by the thickness of the film.

Surface-specific spectroscopy study of buried graphene electrodes, supported on different substrates, reveals that graphene charging is decoupled from the charging of its substrate. The substrate governs the reorganization of interfacial water.

The molecular arrangement of interfacial water upon solid-to-liquid phase transition of lipid molecules was investigated with sub-molecular resolution by 3D AFM.

The hydrophobic adamantane molecule is fully hydrated through vapour codeposition with water onto a cryogenic substrate and the structure of the first hydration shell is studied with neutron diffraction.

Colloidal crystals of DNA-coated nanoparticles transition from face-centered cubic to body-centered cubic structures with increasing salinity; this transition is concurrent with salt-induced dehydration of the grafted DNA.

We perform molecular dynamics simulations of aqueous NaCl solutions at the interface with graphene electrodes, and examine the impact of both ion concentration and electrode potential on interfacial water reorientational dynamics.

XPS and atomically resolved nc-AFM shed light on the interaction of the surface K⁺ ions of muscovite mica with water vapor and liquid water under ultraclean conditions.