Mesoscopic Approach for Disjoining Pressure Effects in Nanoscale Thin Liquid Films on Nanostructured Surfaces

Nanoscale thin liquid films play a pivotal role in diverse natural phenomena and industrial applications, where their evaporation heat transfer characteristics and morphological evolution are critically influenced by disjoining pressure. While classical theories adequately describe this effect on smooth surfaces, the disjoining pressure of liquid films on nanostructured surfaces remains poorly understood. In this work, we propose a mesoscopic model to investigate disjoining pressure effects in nanoscale liquid films on nanostructured substrates, in which long-range solid-fluid interactions are directionally discretized on high-order lattice to enable the treatment of nanostructured surfaces. The model is validated in isothermal and nonisothermal systems, demonstrating its capability to capture disjoining pressure effects on both smooth and nanostructured surfaces. Furthermore, we reveal the fundamental interplay between surface tension and disjoining pressure in dictating the morphology of thin liquid films and provide insights into the Hamaker constants of nanostructured surfaces. A comprehensive stability analysis of thin liquid films on nanostructured surfaces is also presented. This work advances the understanding of microscale mechanisms in liquid-vapor phase change processes and offers a versatile tool for optimizing heat and mass transfer in nanoscale systems.