Efficient Fabrication of Wear-Resistant PEEK Matrix Composite Coating with Superhydrophobicity for Self-Cleaning and Anti-Icing Applications

For the potential application of superhydrophobic surface to anti-icing of Unmanned Aerial Vehicle(UAV) metal wing,a gradient composite coating was successfully prepared on the common aviation metal 7075Al alloy substrate by electrostatic spraying, with Polytetrafluoroethylene(PEEK) and Polytetrafluoroethylene(PTFE) as raw materials for physical blending. The composite structure was constructed by doping the modified hydrophobic silica(k-SiO2) particles. The wettability, microtopography and chemical components of coating were characterized by contact angle tester, SEM and FT-IR respectively. Results showed that the Water Contact Angle(WCA) of PEEK-PEEK/PTFE composite coating increased with PTFE content increase, and the maximum WCA could reach 149.6°, PTFE and PEEK were cross-linked to form nanofibers closely arranged on the surface. However, when k-SiO2 particles was were added into it, the PEEK-PEEK/PTFE/k-SiO2 superhydrophobic coating that exhibits WCA of 156.4±1° and Water Contact Sliding(WSA) of 2±0.5° was obtained. Micro-nano multi-scale protrusion surrounded by low surface energy fibrous filamentous structure distributed on the surface, which can entrap air pockets, leading to extremely strong dynamic water repellency. Interestingly, it is found that droplets can bounce back quickly after hitting the surface with shorter solid-liquid contact time of 18.25ms. Moreover, the coating exhibits excellent mechanical wear resistance to withstand 51 abrasion cycles with good adhesion to substrate of grade 0, anti-fouling and anti-scaling abilities. Furthermore, compared with the bare 7075Al alloy surface, the prepared superhydrophobic coating has obvious icing characteristic for the reason of a solid-liquid-gas composite contact surface with droplets, making it an ideal anti-icing surface.