title: Mapping water uptake in organic coatings using AFM-IR.
abstract: The long-term failure of seemingly intact corrosion resistant organic coatings is thought to occur via the development of ionic transport channels, which spontaneously evolve from hydrophilic regions on immersion, i.e., as a result of localized water uptake. To this end, we investigate water uptake characteristics for industrial epoxy-phenolic can coatings after immersion in deionized water and drying. Moisture sorption and the changing nature of polymer-water interactions are assessed using FTIR for dry and pre-soaked films. More water is found to be absorbed by the pre-soaked coatings on exposure to a humid environment, with a greater degree of hydrogen-bonding between the polymer and water. Furthermore, morphological changes are then correlated to localized water uptake using the AFM-IR technique. Nanoscale softened regions develop on soaking, and these are found to absorb a greater proportion of water from a humid environment.
authors.affiliation: Corrosion and Protection Centre, School of Materials, The University of Manchester, The Mill, Sackville St, Manchester, M13 9PL, UK. suzanne.morsch@manchester.ac.uk.
authors.forename: S
authors.initials: S
authors.lastname: Morsch
authors.forename: S
authors.initials: S
authors.lastname: Lyon
authors.forename: P
authors.initials: P
authors.lastname: Greensmith
authors.forename: S D
authors.initials: SD
authors.lastname: Smith
authors.forename: S R
authors.initials: SR
authors.lastname: Gibbon