Water Repellency of Laser-Textured Aluminum Surfaces Compared to its Polymer Imprints

The phenomenon of enhanced water repellency is extensively studied and used in the fabrication of functional materials [1]. However, only a few related methods provide sufficient scalability. The most promising of these is the embossing of a pre-textured metal template onto the surface of the polymer film, especially in combination with roll-to-roll rewinding. In this case, laser ablation with pico- and femtosecond laser pulses ensures the most precise texturing of metal surfaces at the tens of microns scale. Common methods for producing such metal dies are Direct Laser Writing (DLW) or the much faster Direct Laser Interference Patterning (DLIP). Furthermore, laser-induced periodic surface structure (LIPSS) nano-gratings can be obtained. The formation of imprints, in turn, depends not only on the micro- and nanotexture of the die, but also on the parameters of the polymer material. In this work, we studied the water-repellent properties of impints on the surface of polydimethylsiloxane and polyethylene from aluminum dies textured with pico- and femtosecond lasers. The method based on the Cassie-Baxter equation made it possible to determine with sufficient accuracy the fraction of the texture surface that is in contact with the wetting liquid [2].