Surface functionalization of 4H-SiC with biomimetic structures via two-step femtosecond laser processing for superhydrophobicity

A biomimetic superhydrophobic surface was fabricated on single-crystal 4H-SiC using a two-step femtosecond laser processing strategy followed by surface silanization. Drawing inspiration from the micro/nanostructures of butterfly wings and shark skin, a hybrid hierarchical architecture was engineered by first generating microscale grid patterns and then inscribing small grooves within each grid cell. This morphology significantly enhanced surface roughness and provided the structural basis for wettability modulation. Systematic characterization revealed that laser-induced oxidation introduced abundant polar functional groups, resulting in superhydrophilicity, which was subsequently converted into superhydrophobicity (water contact angle ∼ 154°) via octyltriethoxysilane (OTES) modification. The resulting surface exhibited excellent robustness to processing parameters, with superhydrophobicity achieved across a wide range of laser powers (30–110 mW) and grid spacings (50–150  μ m ). EDS and XPS analyses confirmed the transformation of polar oxide species into nonpolar chemical groups following modification. Functional demonstrations showed that the fabricated surface possessed strong self-cleaning and anti-icing capabilities, with water droplets rapidly rolling off to remove contaminants and delaying ice nucleation by over threefold compared to untreated SiC. This work provides a scalable, maskless, and environmentally friendly approach to functionalize SiC surfaces, paving the way for their application in harsh environments such as aerospace, microfluidics, and power electronics.