Interfacial engineering via silane coupling for mechanically robust and multifunctional superhydrophobic SiC/PTFE nanocomposite coatings

Polytetrafluoroethylene (PTFE) is an excellent candidate for superhydrophobic coatings but suffers from poor mechanical durability. This study presents a facile strategy to overcome this limitation by creating a covalently-bonded nanocomposite. A robust superhydrophobic coating via one-step spray deposition of a composite comprising PTFE and perfluorooctyltriethoxysilane (PFOTES)-functionalized silicon carbide nanoparticles (F-SiC) is prepared. The PFOTES modification (optimal at 4 wt%) serves as a critical interfacial engineer, which not only enhances the dispersion and compatibility of nano-SiC within the PTFE matrix but also constructs a uniform, hierarchical micro/nano-roughness essential for extreme water repellency. At an optimal F-SiC loading of 100 wt%, the coating exhibits exceptional superhydrophobicity, with a contact angle (CA) of 170.8 ± 1.1° and a sliding angle (SA) of 2.0 ± 1.1°. More importantly, the strong covalent interface translates into enhanced mechanical durability, as the coating maintains superhydrophobicity after severe tests including 10-cycle tape peeling, 8-m sandpaper abrasion, and 100-min water jet impact. The composite also demonstrates enhanced thermal stability (decomposition onset elevated by >140°C), retains superhydrophobicity after exposure up to 260°C, and shows excellent resistance to salt spray corrosion and prolonged acidic/alkaline immersion. The work establishes that rational interfacial design, achieved through targeted silane coupling, is a potent strategy for developing polymer-ceramic nanocomposite coatings that synergize ease of processing with comprehensive durability, paving the way for their practical application in demanding environments. Download: Download high-res image (154KB) Download: Download full-size image