Controlling the wettability of polycarbonate substrates by producing hierarchical structures using Direct Laser Interference Patterning

[Display omitted] •Structuring approaches for hierarchical micro-structures on polycarbonate via DLIP.•Double-scale high-depth structures with different arrangements of lines and pillars.•Possibility to fabricate highly isotropic or anisotropic structures.•Depth, type and orientation of the structures selectively control the wettability. New strategies for the fabrication of surface structures using Direct Laser Interference Patterning are presented in this work, aiming to fabricate hierarchical structures with selective wetting properties. Polycarbonate sheets have been structured employing a two-beam interference arrangement using an ultraviolet (263 nm) nanosecond-pulsed laser, creating line- and pillar-like structures with simple and hierarchical geometries. Two different methods for producing hierarchical structures are here provided, both relying on a pixel-wise structuring technique and able to achieve high structure depths. The produced surface patterns are characterized by confocal microscopy, scanning electron microscopy and the influence of the surface topography on the water contact angle is investigated. The correlation between structure geometry and wettability response, in terms of structure height and directionality of the droplet shape is reported.