Plasma and thermoforming treatments to tune the bio-inspired wettability of polystyrene

This paper shows the effects on wettability of plasma and thermoforming treatments on 14 different polystyrene (PS) surfaces, with a comparison with a lotus leaf. Quantitative roughness analyses of PS surfaces and lotus leaf, by three-dimensional optical profilometer and scanning electron microscope, have been carried out. We characterized the water drop sliding by measuring the contact angle, sliding angle, sliding volume and sliding speed. A relevant correlation between technological treatment, surface roughness parameters and wetting measurements clearly emerges, suggesting the plasma/thermoforming treatment as a process for enhancing the hydrophilic/hydrophobic behavior of PS surfaces. Determination of the static and resistant forces of the drop sliding on the surfaces concludes the paper.