Resorcinol-formaldehyde resin combining epoxy resin as composite coating with efficient anti-corrosion resistance and anti-biofouling capacity

In marine environments, microbial contamination and corrosion have persistently threatened the integrity of ships and marine equipment, driving the demand for high-performance coatings integrating anti-corrosion and anti-biofouling functionalities. Herein, for the first time, resorcinol-formaldehyde resin (RF) was used as the filler to introduce epoxy resin (EP) to form an RF/EP composite coating with dual-function anti-corrosion and antibiofouling protection. Anti-corrosion resistance tests, including open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), and neutral salt spray (NSS), revealed that the RF/EP-6 composite coating exhibits superior anti-corrosion properties, with an impedance radius of 1.56 x 109 Omega.cm2, which surpasses the impedance of pure-phase EP (3.64 x 106 Omega.cm2) by more than two orders of magnitude. In addition, the composite coating reflected significant anti-biofouling effects against bacteria (E. coli and S. aureus) and algae (Chlorella), with only a low amount of microorganisms being able to adhere to the surface, which was mainly attributed to the incorporation of RF resin, producing strong oxidative active species (center dot OH, center dot O2- and H2O2). Our study introduces an innovative design concept aimed at developing multifunctional coatings that provide both anti-biofouling and anti-corrosion capabilities for marine equipment field.