A multifunctional polymer composite coating assisted with pore-forming agent: Preparation, superhydrophobicity and corrosion resistance

In this paper, a versatile low-cost and simple spraying process was reported for fabricating epoxy resin (EP)/fluorinated ethylene propylene (FEP)/modified ZnO (m-ZnO) superhydrophobic coating (EP/FEP/m-ZnO). The ZnO nanoparticles were modified by the low surface-energy material of stearic acid, and the pore-forming agent (NH4HCO3) was used to build micro/nano-structures. Results showed that the composite coating with 32 wt.% of m-ZnO, 5 wt.% of NH4HCO3 exhibits the optimum superhydrophobicity, with water contact angle (WCA) of 160° and sliding angle of 2°. More importantly, the WCA of the as-prepared composite coating still maintains more than 130° under strong acid or 3.5 wt.% NaCl aqueous solution for 270 h immersion, which demonstrates the excellent anti-corrosive performance of EP/FEP/m-ZnO superhydrophobic coating. The WCA of the EP/FEP/m-ZnO coating still kept 136° and only gained weight loss of 1.04% after being rubbed with 300 cycles, and the weight loss of EP/FEP coating is 18.85% under the same condition. All the above aspects are the direct evidences for the highest wear resistance of EP/FEP/m-ZnO superhydrophobic coating. Furthermore, the adhesive ability of the EP/FEP/m-ZnO composite coating was satisfied with the requirements of Grade 1, that standing for strong adhesion between the coating and substrate. Simultaneously, the soil and fly ash could be easily cleaned from the surface of superhydrophobic coating with flowing droplets, that showing unique self-cleaning property. Furthermore, the EP/FEP/m-ZnO superhydrophobic coating has excellent anti-corrosion performance. It is believed that the nano/micro structure formed by the inorganic filler m-ZnO and pore-forming agent of NH4HCO3 plays an important role. The suitable magnitude of pores has a positive meaning on fabricating the EP/FEP/m-ZnO superhydrophobic coating. The multifunctional coating has a high application value in condition of wear resistance, self-cleaning and anticorrosion, this facile and economic method may offer an effective strategy for surface and interface science and even industrial production.