Sub-micron calcium carbonate as a template for the preparation of dendrite-like PANI/CNT nanocomposites and its corrosion protection properties

The dendrite-like polyaniline/carbon nanotube (PANI/CNT) nanocomposites have been successfully prepared through the oxidative polymerization of aniline on the surface of nanocomposites of sub-micron calcium carbonate composites and CNT, in acid aqueous solution. With calcium carbonated composing, the adherent dendrite-like PANI forms on the CNT surface. The possible mechanism is the turbulence around CNT due to the gas carbon dioxide formed by decomposition of calcium carbonate template, that leads to forming this unique composite morphology. The obtained PANI/CNT nanocomposites exhibit excellent redox capability not only in acidic but also in neutral medium due to the interfacial pi-pi interactions between CNT and PANI. The PANI/CNT nanocomposites are found to be easily dispersed into the aqueous waterborne acrylate-amino (AA) resin. The AA coating filled with PANI/CNT has 76 days resistance against 3.5 wt% NaCl solution at 65 degrees C, which is higher than 29 days for the AA coating contained PANI and much higher than 60 h for the unfilled AA coating. The superior corrosion protection mechanisms are revealed to be the labyrinth effect of nanocomposites and anodic protection of passivation film. Therefore, this strategy and nanocomposite platform may have high potential in corrosion protection area.