Article ID: 23-19NR_OA
This study experimentally investigated the wetting transition behavior of deposited fakir droplets and in-situ condensed droplets on different microstructured surfaces. Diamond-like carbon was introduced as the substrate for superhydrophobic surfaces (SHS) to enhance the durability of the microstructure and ensure the repeatability of the experiment data. An important outcome of this study is demonstrating a slippery superhydrophobic surface with a low depinning force that suppresses the transition from the Cassie–Baxter state to the Wenzel state for microdroplets less than 0.37 mm in diameter. By selecting an appropriate pillar pitch and employing tapered micropillars with small pillar widths, the solid-liquid contact at the three-phase contact line was reduced, and low depinning forces were obtained. In the case of in-situ condensed droplets, the interface of the SHS was modified by introducing multiscale roughness via the coating of nanoparticles on the micropillars; and by enclosing the micropillars with walls. The new interface could also effectively suppress the wetting transition of condensed droplets (for drop diameter > 900 μm) during their growth via merging with neighboring droplets. The SHS with the modified interface is expected to show better performance for dropwise condensation and anti-icing.
