Timothy S. Groves | Searcharxiv

arXiv2026

Viscoelastic interfacial structures in undersaturated calcium solutions under nanoconfinement

Calcium mineralisation underpins processes ranging from biomineralisation to scalable carbon storage, yet the earliest stages of nucleation remain unresolved. Here we investigate calcium-containing solutions under nanoscopic confinement while remaining undersaturated with respect to bulk calcium carbonate precipitation. Using sensitive surface force measurements, we identify a long-range non-DLVO repulsive interaction specific to calcium solutions, which we attribute to hydrated ion networks at mineral interfaces. These interfacial networks exhibit viscoelastic behaviour distinct from the bulk solution, persist across a broad pH range, and can be disrupted by competing ions with strong surface affinity. Our findings provide experimental evidence that stable hydrated ion networks can emerge at mineral interfaces under undersaturated conditions, supporting the possibility that interfaces and confinement stabilise intermediate ion assemblies prior to nucleation. These results bridge classical and nonclassical descriptions of mineral nucleation and highlight the central role of interfaces and confinement in directing crystallisation pathways.

cond-mat.soft↗

arXiv2024

Wave mechanics in an ionic liquid mixture

Experimental measurements of interactions in ionic liquids and concentrated electrolytes over the past decade or so have revealed simultaneous monotonic and oscillatory decay modes. These observations have been hard to interpret using classical theories, which typically allow for just one electrostatic decay mode in electrolytes. Meanwhile, substantial progress in the theoretical description of dielectric response and ion correlations in electrolytes has illuminated the deep connection between density and charge correlations and the multiplicity of decay modes characterising a liquid electrolyte. The challenge in front of us is to build connections between the theoretical expressions for pair correlation functions and the directly measured free energy of interaction between macroscopic surfaces in experiments. Towards this aim, we here present measurements and analysis of the interactions between macroscopic bodies across a fluid mixture of two ionic liquids of widely diverging ionic size. The measured oscillatory interaction forces in the liquid mixtures are significantly more complex than for either of the pure ionic liquids, but can be fitted to a superposition of two oscillatory and one monotonic mode with parameters matching those of the pure liquids. We discuss this empirical finding, which hints at a kind of wave mechanics for interactions in liquid matter.

cond-mat.soft↗