Method for predicting the wettability of micro-structured surfaces by continuum phase-field modelling

Numerical prediction of material properties is attracting the attention of the scientific community and industry because of its usefulness in the design process. In the fields of fluid dynamics and microfluidics, several simulation methods have been proposed and adopted to evaluate the properties of surfaces and material interfaces, thanks to the increasing computational power available. However, despite the efforts made, a general and standardized methodology for implementing such methods is still lacking, thus requiring a trial-and-error approach for each new problem, making them difficult to implement and creating a bottleneck at the initial stage of surface design. Here, we report a validated protocol to evaluate the wettability of micro-structured surfaces with a phase-field model. Summarizing: - Simulating physical phenomena with multi-phase flows and moving contact lines can be a challenging task, due to the coupling among disparate length scales. - Using the Cahn-Hilliard diffuse-interface model, moving contact lines can be extensively investigated, although difficulties may arise when implementing numerical simulations, e.g., model parameter calibration, selection of boundary conditions, post-processing of fluid dynamics/equilibrium. - A method for employing this model and evaluating the physical consistency of the results is proposed here, considering the wettability of micro-structured surfaces as a case study.