Enhancing Hot Droplet Repellency of Superhydrophobic Surfaces by Adding Macrotextures

Superhydrophobic surfaces are known for their ability to repel water, minimizing contact time and reducing heat transfer from hot drops. However, drops that bounce on a superhydrophobic surface when warm can stick if they approach evaporation temperatures or the melting point of microtexture material. This phenomenon is likely due to evaporated vapor from the drop condensing on the solid surface, causing the drop to transition into a Wenzel state or surface to lose its roughness due to melting. This presents a challenge to identify materials or surface coatings that can overcome this limitation. In this research, we examine superhydrophobic surfaces modified with macro-textures that effectively split water drops into smaller droplets. By analyzing impact dynamics and heat transfer modifications, we aim to determine the surface topology that most effectively enhances the ability of superhydrophobic surfaces to repel hot drops. Understanding this can aid in developing materials that better prevent burns from scalding water.