Atomistic insights into the nanofluid transport through an ultra-confined capillary

Bio-Inspired Adhesion Control with Liquids

Bio-inspired surfaces enabling wet adhesion management are of significant interest for applications in the field of biomedicine, as components of bionic robots and as wearable devices. In the course of biological evolution, many organisms have evolved wet adhesive surfaces with strong attachment ability. Insects enhance their adhesion on contact substrates using secreted adhesive liquids. Here we discuss concepts of bio-inspired wet adhesion. First, remaining challenges associated with the understanding and the design of biological and artificial wet adhesive systems as well as strategies to supply adhesive liquids to their contact surfaces are reviewed. Then, future directions to construct wet adhesive surfaces with liquids are discussed in detail. Finally, a model of wet adhesion management with liquids is suggested, which might help the design of next-generation bio-inspired wet adhesive surfaces.

A Deep Look into the Dynamics of Saltwater Imbibition in a Calcite Nanochannel: Temperature Impacts Capillarity Regimes

This research concerns fundamentals of spontaneous transport of saltwater (1 mol·dm^-3 NaCl solution) in nanopores of calcium carbonates. A fully atomistic model was adopted to scrutinize the temperature dependence of flow regimes during solution transport under CaCO₃ nanoconfinement. The early time of capillary filling is inertia-dominated, and the solution penetrates with a near-planar meniscus at constant velocity. Following a transition period, the meniscus angle falls to a stabilized value, characterizing the capillary-viscous advancement in the calcite channel. At this stage, brine displacement follows a parabolic relationship consistent with the classical Lucas-Washburn (LW) theory. Approaching the slit outlet, the meniscus contact lines spread widely on the solid substrate and brine leaves the channel at a constant rate, in oppose to the LW law. The brine imbibition rate considerably increases at higher temperatures as a result of lower viscosity and greater tendency to form wetting layers on slit walls. We also pointed out a longer primary inertial regime and delayed onset of the viscous-capillary regime at higher temperatures. Throughout the whole span of capillary displacement, transport of sodium and chloride ions is tied to dynamics and diffusion of the water phase, even at the mineral interface. The results presented in this study are of broad implications in diverse science and technological applications.