Semi-empirical and computational modelling of the laser structuring effect on wettability performance of polypropylene

Developing laser-textured surfaces to achieve a target wettability remains a time-consuming process, as texture selection often relies on trial-and-error approaches. To contribute to a more systematic design strategy, this study proposes a methodology to support and accelerate the selection of feature dimensions to achieve a target wettability. The approach combines a 3-factor, 3-level Design of Experiments with computational phase field modelling to evaluate the wettability of laser textured polypropylene surfaces. Square pillar textures were developed, and the effects of pillar width, cavity width and pillar height on the measured Contact Angle (CA) was quantified. The experimental results showed that pillar height was the most influential parameter, and a simplified regression model was proposed to describe its effect on contact angle variation. In parallel, a 2D computational Phase Field model implemented in COMSOL Multiphysics 5.4, was developed to support the rapid selection of texture dimensions for targeted wettability. Model parameters were calibrated and validated using experimental contact angle measurements, showing good agreement within the investigated texture range. Overall, the combined DoE–simulation framework provides additional information on how surface topography affects contact angle variations and helps guide texture design, reducing experimental trial-and-error steps for the considered scenario.