Superior anti-corrosion and self-healing bi-functional polymer composite coatings with polydopamine modified mesoporous silica/graphene oxide

In this article, graphene oxide (GO) and benzotriazole-loaded mesoporous silica nanoparticles (BTA/MSNs) are combined on micro scale through the in situ polymerization of polydopamine (PDA), preparing a self-healing bi-functional GO (fGO) used as nano-fillers for anti-corrosion enhancement of waterborne epoxy (WEP) coatings. Scanning electronic microscopy (SEM) images show that the BTA/MSNs are uniformly distributed on the surface of high aspect ratio GO nanosheets to endow GO nanocontainer characteristics. UV-vis profiles demonstrate that fGO has pH-controlled release function. Modulus at lowest frequency is generally used for comparing the corrosion resistance of organic coatings. Modulus at lowest frequency (1.42 × 107 Ω cm2) after 30 days immersion in 3.5 wt.% NaCl solution revealed 2 orders of magnitude higher that of blank WEP (1.17 × 105 Ω cm2). With artificial cracks on its coatings, fGO/WEP had no obvious rust compared with blank WEP after 240 h of immersion. We anticipate that self-healing and physical barrier bi-functional nanocontainers improve the traditional anticorrosion coating efficiency with better, longer-lasting performance for shipping, oil drilling or bridge maintenance.