Preparation of super-hydrophobic surface with micro-nano layered structure on 316 stainless steel wet chemical method

In order to simplify the traditional preparation procedure of super-hydrophobic stainless steel (SLS), a novel one-step method was developed to produce super-hydrophobic surface on 316 SLS under the simultaneous chemical etching and surface modification with cofunction of hydrogen peroxide (H2O2), hydrofluoric acid (HF) and per-fluorooctyl trichlorosilane (PFOS). The effects of the mixing ratio of reagents (H2O2, HF and PFOS) and reaction time were explored by orthogonal experiments. The results indicated that H2O2 showed the most significant effect on the hydrophobicity of SLS. When the molar ratio of H2O2/HF ranged between 0.2/1-0.4/1, the prepared samples showed excellent super-hydrophobicity, with the maximum water contact angle of 161.78 degrees and the minimum slip angle of 1.94 degrees. The influencing mechanism of H2O2 on the etching and modification was further explored by X-ray photoelectron spectroscopy (XPS) and Scanning electron microscopy (SEM). The results showed that the ratio of H2O2/HF markedly affected the grafting of PFOS onto the surface of SLS. According to the tests of corrosion resistance and durability, the corrosion resistance of super-hydrophobic surface was 6 times higher than that of raw SLS, and the super-hydrophobicity of SLS hardly changed after 3 months of exposure in the ambient air. The water contact angle was still close to 150 degrees after peeling adhesive tape for 12 times. The results of this study indicated a promising perspective for industrial application of the one-step method.