In their Physical Review E article, prof. Malijevský et al. present a detailed theoretical and numerical study of complete wetting and drying phenomena at sinusoidally corrugated walls. By analyzing how interfacial adsorption behaves near saturation, the authors uncover how wall geometry and interaction range determine the structure of fluid interfaces.
Two regimes are examined: complete drying with short-ranged (SR) interactions and complete wetting with long-ranged (LR) van der Waals forces. Using density functional theory (DFT) alongside nonlocal Hamiltonian theory (for SR systems) and the sharp-kink approximation (for LR systems), the study derives precise scaling laws for the film height and its corrugation.
For SR systems, the interface height deviation from planar walls scales quadratically with wall amplitude at small values, with a crossover to a linear regime with logarithmic correction for stronger corrugations. The corrugation amplitude decays linearly with the chemical potential deviation from saturation δμ. In contrast, LR systems exhibit different scaling: the height deviation scales as δμ1/3, and the corrugation amplitude as δμ4/3. These predictions are strongly corroborated by DFT simulations.
To summarize, the study presents a new mesoscopic theory confirmed by microscopic modelling, exposing the critical role of wall geometry and interaction range in controlling interfacial phase behavior. Its insights are broadly relevant to nanofluidics, wetting control, and the design of structured surfaces. Future extensions toward more complex geometries and nonequilibrium systems include, e.g., active matter near rough walls.
A representative equilibrium density profile near a sinusoidal wall. The green line defines the liquid-gas interface, which is corrugated at a nanoscale
- Malijevský A.*, Pospíšil M., Magočiová M., Janek J.: Complete wetting and drying at sinusoidal walls. Phys. Rev. E 2025, 112, 015502. doi.org/10.1103/2d7c-6t3t