Stability and water wetting behavior of superhydrophobic polyurethane films created by hot embossing and plasma etching and coating
Abstract
The surface characteristics, the stability against erosion, and the water wetting behavior of superhydrophobic polyurethane (PU) films are described. Hot embossing is used to imprint conical microstructures in PU films. Afterwards, about 200‐nm thick hydrophobic plasma polymers are deposited by PECVD, using different fluorocarbons (CHF3, C3F6, or C4F8) or hexamethyldisiloxane as precursors. Ar or O2 plasma etching is used to increase the surface nanoroughness. The plasma coatings show stability against sand abrasion and in a long‐term outdoor test but are completely degraded by an industrial UV/water weathering test. Superhydrophobicity is achieved on the coated microstructures with base diameters between 35 µm and 50 µm, top diameters between 14 µm and 20 µm, and distances between 50 µm and 70 µm.
