In situ monitoring of organic coating swelling by dynamic mechanical analysis and scanning electrochemical microscopy

It is shown that the maximum dimensional changes of the DGEBA/DAMP resin during the water absorption are about 5% for the coatings while they are only about 2% for the free films. This difference can be explained by the fact that, in the case of the coating, the metal substrate can constrain the polymer in the plane which affects the swelling upon water absorption by the relaxation of internal stresses developed during the curing process. We also mention the technical aspects when using SECM and DMA as convenient methods to evaluate the swelling.