Sustainable and Scalable Fabrication of Fluorine-Free Superhydrophobic Ceramic Surfaces via Laser Texturing and Silicone Oil Heat Treatment

Superhydrophobic (SHPo) ceramic surfaces with water contact angles exceeding 150° are highly desirable for demanding applications in aerospace, optics, biomedical devices, and harsh environment engineering due to their potential for self-cleaning, anti-icing, corrosion resistance, and reduced fluid drag. However, their widespread practical adoption is often hindered by process complexity, concerns over thermal durability, and the prevalent reliance on persistent, bioaccumulative, and toxic fluorinated compounds, which pose significant environmental and health risks. In this work, we present a rapid, sustainable, and scalable fabrication strategy to achieve fluorine-free SHPo surfaces on technical ceramics. By combining direct nanosecond laser texturing with a rapid and eco-friendly postprocess, namely a 10 min heat treatment using nontoxic silicone oil, we successfully fabricated SHPo surfaces on single-crystal sapphire (Al2O3) and titanium dioxide (TiO2) substrates. This simple thermal treatment accelerates the adsorption of hydrophobic organic groups onto the laser-activated ceramic surface, creating a stable, low-surface-energy layer without hazardous chemicals. We demonstrate that the laser areal fluence, a composite parameter, serves as an effective tool for precisely tuning surface morphology and, consequently, the water adhesion behavior, from low-adhesion, rolling states to high-adhesion, pinned states on these inherently hard and inert materials. This capability to engineer differential adhesion on a single substrate opens avenues for advanced applications in controlled droplet manipulation and microfluidics on ceramic platforms. Furthermore, the long-term stability of the surfaces was evaluated after 3 years in ambient air, and the excellent performance of the SHPo ceramic surface was demonstrated through the water bouncing effect and the self-cleaning effect. This research provides a versatile, environmentally benign, and industrially scalable pathway for manufacturing multifunctional SHPo ceramics.