UV-cured electroactive polyurethane acrylate coatings with superhydrophobic surface structure of biomimetic peacock feather for anticorrosion application

In this work, UV-cured electroactive polyurethane acrylate (EPU) materials with the superhydrophobic surface structure of biomimetic peacock feather were firstly prepared and applied in anticorrosive coatings. Firstly, amine-capped aniline trimer (ACAT) and vinyl-capped aniline trimer (VCAT) were synthesised and characterised by H-1-nuclear magnetic resonance spectroscopy (NMR), Fourier transform infrared spectroscopy (FTIR) and mass spectroscopy. Polyurethane acrylate (PUA) was synthesised and characterised by H-1 NMR and FTIR spectroscopy. EPU was then prepared through the UV curing of PUA with 0, 1, 3 and 5 wt% VCAT (named EPUO, EPU1, EPU3 and EPU5, respectively) and characterised via FTIR. The redox capabilities of the as-prepared EPU series were investigated by cyclic voltammetry studies. EPU with higher VCAT loading (EPU5) exhibited better corrosion protection performance than those with lower VCAT loadings (EPUO, EPU1 and EPU3) based on a series of electrochemical corrosion measurements because of the formation of a dense metal oxide layer as evidenced by Raman spectroscopy. Moreover, EPU5 with the surface structure of biomimetic peacock feather (denoted by BEPU5) was prepared by nanocasting technique with polydimethylsiloxane as the flexible transparent negative template. The surface morphology and wettability of BEPU5 was investigated by scanning electron microscopy and contact angle (CA) analysis. The CA of BEPU5 remarkably increased to 145 degrees compared with that of EPU5 63 degrees. This massive increase in CA indicates efficient superhydrophobic properties, which were induced by the biomimetic peacock feather and produced outstanding corrosion protection performance for short and long terms based on a series of electrochemical corrosion measurements. This study is the first of its type to produce a biomimetic feather with massive increase in superhydrophobic properties, which is expected to revolutionise biomimetic industrial coating technologies towards better corrosion protective coatings.