Fabrication of micro-structured surfaces by additive manufacturing, with simulation of dynamic contact angle

Highlights: • Direct fabrication of the components with micro structured surfaces by digital light processing method. • Digital Light Processing method was pushed to its limit for fabrication of the components with micro holes. • Measurement of the components with micro holes present uniformity of the print in different areas of the structure. • The printed substrate realized hydrophobicity on the hydrophilic materials (intrinsic contact angle of 65°). • 3D dynamic impact behavior simulation for contact angle prediction was used to estimate wettability of the surface. -- Abstract: This work presents an Additive Manufacturing (AM) based method for production of components with micro-structured surfaces. Vat photopolymerization was used for the experiments by an AM custom-build machine at the Technical University of Denmark (DTU). Components with micro holes were printed in different sizes and the uniformity of them analyzed. Subsequently, in order to assess the functionality of the surface, the water droplet contact angle was measured to evaluate the wettability of the different components with micro holes. It was found that it was possible to fabricate the components with micro holes using precision AM process. The printed substrate exhibited hydrophobicity as a hydrophilic material (intrinsic contact angle of 65°). A hydrophobic surface was achieved with the printed features exhibiting a maximum contact angle of 113°. Additionally, the volume of fluid (VOF) method was employed to predict the surface contact angle. The predicted results were validated by comparison against the experiments. The average value from experiments was predicted by the model. However, it was noted that the cross-sectional height profile of the structures and the surface roughness of the printed samples, were not precisely replicated as designed, which slightly affects the prediction results, though, similar prediction trend was observed.