Electrolyte transport in polymer barrier coatings: perspectives from other disciplines

Large infrastructure for transportation, energy transmission, water supply etc., must survive for many decades with their carbon steel components protected against corrosion by organic polymer coatings. Modern, environmentally responsible coatings are replaced more frequently than was necessary for some older coating technologies. In order to find useful, additional insights, this review is based on ideas and information from other topics rather than from conventional coatings sources. There is considerable research done on desalination membranes, batteries, and the nervous system that seems useful in understanding better how the composition of polymers affects their barrier properties. Typical crosslinked coatings have characteristics and defects that limit their performance. Very few molecules of water are required to enable corrosion, so improvement of barrier properties requires considerable control over the composition of a coating. There is no common mechanism of how barrier coatings deteriorate, but behavior seems to fall between two patterns. More successful coatings seem to fail slowly due to degradation of the coating upon exposure but less successful coatings fail faster and progressively by mechanisms that have yet to be clarified. Some information and ideas, from non-coating disciplines, are presented delete comma that may be worthy of investigation.