Electrochemical Properties of Polymer Protective Coatings on a Platinum Substrate when Exposed to Aggressive Media

摘要

A promising direction for improving protective polymer coatings for highly aggressive environments is the implementation of the mechanism of self-adaptation and increase of the protective properties of the coating, as well as self-healing. In multilayer composite coatings, in addition to primer layers, this approach is relevant for insulating upper layers based on thermosets. Such modern materials, as a rule, contain active functional groups and oligomeric additives. This paper presents the results of a study of the electrochemical characteristics (EIS and potentiometry) of polymeric epoxy protective coatings on an inert platinum substrate during long-term exposure to NaCl solution. It is shown that, when active organic additives are used in a polymer coating, it is fundamentally possible to find the effect of self-adaptation and an increase in the protective properties (impedance modulus, active resistance, angle of loss of the polymer film, and an increase in the potential of the substrate under it) when exposed to a chloride-containing aggressive environment. At the stage of the beginning of coating destruction at a certain time intervals for a model epoxy-phenol-furan coating, a behavior was registered that allows us to speak about the manifestation of the self-healing effect, namely, the restoration (up to 100%) of the full coating impedance combined with the restoration of a high (up to 89 degrees) dielectric loss angle.