UV-curable nanocasting technique to prepare bio-mimetic super-hydrophobic non-fluorinated polymeric surfaces for advanced anticorrosive coatings

In this study, a UV-curing nanocasting technique was first used to develop advanced anticorrosive coatings with bio-mimetic Xanthosoma sagittifolium leaf-like, non-fluorinated, super-hydrophobic polymeric surfaces. First of all, a transparent soft template with negative patterns of Xanthosoma sagittifolium leaf was fabricated by thermally curing the PDMS pre-polymer in molds at 60 °C for 4 h, followed by detaching the PDMS template from the surface of the natural leaf. Epoxy-acrylate coatings with biomimetic structures were prepared by performing the UV-radiation process after casting UV-curable precursor with photo-initiator onto a cold-rolled steel (CRS) electrode using the PDMS template. Subsequently, the UV-radiation process was carried out by using a light source with an intensity of 100 mW cm 2 with an exposing wavelength of 365 nm. The surface morphology of as-synthesized epoxy-acrylate coatings obtained from this UV-curing nanocasting technique was found to have lots of micro-scaled mastoids, each decorated with many nano-scaled wrinkles and was investigated systematically by scanning electron microscopy (SEM) and atomic force microscopy (AFM). It should be noted that the water contact angle (CA) of coating with bio-mimetic natural leaf surface was 153°, which was found to significantly higher than that of the corresponding polymer with a smooth surface ( i.e. , CA = 81°). The significant increase of the contact angle indicated that this bio-mimetic morphology exhibited effectively water-repelling properties, implying that it may be a potential candidate as advanced anticorrosive coating materials, which can be identified by series of electrochemical corrosion measurements. For example, it should be noted that the corrosion potential ( E corr ) and corrosion current ( I corr ), respectively, was found to shift from E corr = −730 mV and I corr = 5.44 μA cm −2 of coating with smooth surface (SS) to E corr = −394 mV and I corr = 2.30 μA cm −2 of coating with biomimetic super-hydrophobic surface (SPS). Advanced anticorrosion coating materials were prepared by mimicking curable Xanthosoma sagittifolium leaf-like super-hydrophobic UV-polymeric surfaces using a nanocasting technique.