Anti-corrosion superhydrophobic micro-GF/micro-TiB2/nano-SiO2 based coating with braid strengthening structure fabricated by a single-step spray deposition

Abstract

Superhydrophobic surfaces with self-cleaning, anti-biofouling and corrosion resistance merits are attractive for applications in major engineering fields. Generally, these surfaces possess low-surface-energy chemistry and micro- or nanoscale surface roughness. However, rough surfaces are fragile and highly susceptible to abrasion for high local pressures under mechanical load, causing loss of superhydrophobicity. In this study, we proposed a "fiber weaving/hard particles embedding-soft membrane" strategy to construct a kind of organic-inorganic composite coating by embedding micro-glass fiber (GF)/micro-TiB2/nano-SiO2 particles into the polydimethylsiloxane (PDMS)@polyurethane (PU) for fabricating robust superhydrophobic coating. The addition of micro-nano ceramic particles plays two roles including "hard" micro-skeletons to overcome vulnerable issue of "soft" organic membrane and creation of wear-resistant bearing points on the surface. Furthermore, "soft" membrane can absorb stress when subjected to external mechanical force and PU serves as an adhesive to improve interfacial bond strength. Additionally, GF intersperses in the coating, providing anchoring effect and PDMS serves as a modifier to decrease surface energy. Consequently, the proposed hybrid coating could simultaneously augment its mechanical robustness and multifunctional performance, breaking the notorious "trade-off" restriction of superhydrophobic coating. The preparation parameters and operation condition on the performance of the coating were investigated systematacially. The optimized superhydrophobic coating exhibits the highest water contact angle (WCA) of 167.3° ± 3.9°, the lowest sliding angle (SA) of 4.6° ± 1.3°, corrosion protection efficiency of 95.7 % in 3.5 wt% NaCl solution, with exceptional self-cleaning, anti-pollution, adaptability to various substrates, thermostable, anti-icing and mechanical stability properties, among the top-tier multifunctional performance. The inherent properties of micro-glass fiber, micro-TiB2 and nano-SiO2 ceramics and their highly ordered arrangement in the superhydrophobic coating are expected to provide an effective and versatile design proposal for potential applications in corrosion protection.