Self-healing protection of paint coatings with inhibitor-loaded mesoporous SiO-2 nanoparticles

摘要

Incorporation of nanocontainers loaded with corrosion inhibitor into coatings could provide a self-healing effect during the corrosion process. The self-healing ability occurs due to release of entrapped corrosion inhibitors in response to pH changes produced at the anodic and/or cathodic areas during the corrosion process. However, to successfully achieve this behaviour the nanocontainers should be homogeneously distributed in the coating and should be able to control the inhibitor release to heal the defects. In the present work, mesoporous silica particles have been employed as a carrier for four different corrosion inhibitors: cerium(lll) nitrate, sodium phosphomolybdate, sodium vanadate and zinc chromate. The latest was considered only as a reference for comparison purposes. To improve controlled release, a multilayer shell was then assembled on the inhibitor-loaded silica nanoparticles by the layer-by-layer (LbL) technology with electrostatic assembly of oppositely charged species. A clear coating has been used for the incorporation of the prepared encapsulated loaded nanoparticles. The corrosion behavior and self healing ability of the coatings have been studied by means of Electrochemical Impedance Spectroscopy (EIS) and Scanning Kelvin Probe (SKP).