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Transport of active species (i.e., ions) leaching from pigment particles incorporated in a polymer matrix is the main mechanism behind the anticorrosive performance of protective coatings. Understanding this mechanism is necessary for the effective design of the systems utilizing pigments less toxic than the most efficient chromate salts. It was demonstrated that anticorrosive pigment particles can themselves facilitate the transport of active species via the pathways formed after pigment leaching from a coating. It was also suggested that other paint components, e.g., certain additives, pigments, and fillers can be involved in the formation of transport pathways. Investigation of the possible influence of inert pigment (TiO2) on creating the pathways for chromate ion transport in polymer coatings was the primary objective of this work. In an experiment mimicking the transport of pigment species (i.e., chromate ions), a model epoxy coating containing particles of a single pigment (TiO2) was exposed to a chromate solution (aqueous, or with the addition of acetone as a polymer swelling agent). It was shown that the chromate ions can be transported in the epoxy film preferentially via the TiO2 particles/polymer matrix interface. [ABSTRACT FROM AUTHOR]

• Mechanism of chromate ion transport in epoxy film with BaSO 4 particles has been investigated. • Chromate ion transport progressed via the interconnected BaSO 4 particles. • BaSO 4 particles were shown to leach out from epoxy film. • Pigment Volume Concentration influenced the transport mechanism. A transport mechanism of anticorrosive pigment species (i.e. chromates) in polymer films was investigated. This mechanism plays a crucial role in the performance of anticorrosive polymer coatings which relays on leaching of active anticorrosive species from sparingly soluble pigment particles distributed in the coating. Except for anticorrosive pigments other particles are included in coatings such as pigments with different functions or fillers.The goal of this work was to investigate how filler particles with no anticorrosive function (i.e. BaSO 4) could be involved in formation of the pathways for chromate ion transport. Polymer films containing BaSO 4 particles with different pigment volume concentration (PVC) were exposed to chromate solution allowing migration of chromate species. [ABSTRACT FROM AUTHOR]