Influence of Additive Manufacturing Parameters and Surface Treatments on Wettability of VPP Acrylic Resins.

There is a growing industrial interest in the development of functional plastic surfaces with hydrophobic and easy-to-clean properties, particularly in manufacturing sectors where safety, hygiene, and durability are critical requirements. This work investigates the development of hydrophobic and superhydrophobic surfaces on acrylic resin components fabricated by vat photopolymerisation (VPP), using a high-performance Rigid 10K photopolymer. The influence of manufacturing parameters, namely layer thickness and build orientation, on initial wettability was first evaluated, showing that orientation plays a more relevant role than layer thickness in controlling the water contact angle. Subsequently, different surface modification strategies were explored, including femtosecond laser microtexturing, sandblasting, and physical vapour deposition (PVD) coatings. Preliminary results indicate that femtosecond laser texturing enables controlled modification of surface roughness and wettability, with strong dependence on laser fluence and pitch. Sandblasting significantly increases surface roughness, promoting hydrophobic behaviour through the generation of irregular topographies. In contrast, PVD coatings appear to modify wettability primarily through surface chemistry. Roughness analysis suggests that, although layer thickness governs the initial surface condition, post-processing treatments progressively dominate the final surface morphology. Ongoing work is focused on fully correlating roughness parameters, surface morphology, and wettability performance. Overall, the combination of VPP and tailored surface treatments presents a promising approach for functionalising polymeric surfaces for advanced engineering applications.