Flexible and thermally stable superhydrophobic surface with excellent anti-corrosion behavior

Superhydrophobic films with excellent flexibility, mechanical robust and thermally stable properties have been fabricated through a facile one-step spray-coating process based on bisphenol A based benzoxazine (BA-a), polyurethane (PU) prepolymer, and mesoporous SiO2 (SBA-15). The curing mechanism between BA-a and PU prepolymer morphologies, water contact angles and thermal stability of coatings were characterized and discussed. In addition, the corrosion behavior of the superhydrophobic coatings on the tin plate was characterized by the polarization curve and electrochemical impedance spectroscopy. The coatings made by different weight ratios of BA-a to PU can maintain a contact angle higher than 150°; meanwhile, the coatings had a micro-nano structure with a Tg more than 221 °C. The coatings can be bent by the finger which illustrates their excellent flexible properties. Furthermore, friction coefficient of coatings can reach 1.70. The electrochemical corrosion test results indicated that the superhydrophobic coatings possessed excellent corrosion resistance (Icorr can reach 8.90 × 10−5 A cm−2 with certain ratio), which could have a potential at harsh environment.