Electro-Assisted Deposition of Polypropylene-Infused Nano-Engineered Smart Ni-SiC-TiO₂ Co-Deposited Superhydrophobic and Corrosion-Resistant Coatings on Surgical Steel

Abstract Polypropylene-infused (PP) Novel Ni-SiC-TiO₂ (First time reported ) nano-engineered composite Superhydrophobic (SH) coatings were fabricated on surgical stainless steel via electro-assisted co-deposition to obtain superhydrophobic and corrosion-resistant surfaces for biomedical applications. The electrodeposited coatings developed a hierarchical micro/nanostructure, inducing a wettability transition from the Wenzel to the Cassie-Baxter regime. The water contact angle (WCA) increased from 95° for bare steel to 155° for the Ni-SiC-TiO₂ coating and further to 162° after polypropylene modification, corresponding to an effective solid-liquid contact fraction of 5%. Surface energy analysis using Owens-Wendt and Fowkes models revealed a reduction in total surface energy from 29 mN m⁻¹ for bare steel to 2.6-3.7 mN m⁻¹ for the modified coating, confirming polymer-induced surface energy minimization. Structural analyses confirmed refined grain size and dendritic nanoflower-like morphology resulting from the synergistic incorporation of SiC and TiO₂ nanoparticles. Electrochemical impedance spectroscopy (EIS) demonstrated significantly enhanced corrosion resistance, with the charge-transfer resistance (Rct) increasing from 1.0 × 10⁴ Ω·cm² for bare steel to 5.0 × 10⁴ Ω·cm² for Ni-SiC coatings and reaching 1.35 × 107 Ω·cm² for the polypropylene-modified superhydrophobic coating. The superior performance arises from the combined effects of hierarchical roughness, air entrapment, and polymer-induced surface sealing.