Surface morphology and chemistry of epoxy-based coatings after exposure to ultraviolet radiation

► XPS analysis showed evidence of an oxidative photo-degradation process. ► Surface changes are occurring at early exposure times, in bulk the cracks continue. ► The concentration of the aliphatic group is dominating in the epoxy surface. ► Only little of carbonyl and carboxyl groups are present at the surface. ► They increase relative to the aliphatic and hydroxyl groups as UV time increase.