Scientists at the Instituto de Ciencia y Tecnologia de Polimeros (ICTP) and Centro Nacional de Investigaciones Metalurgicas (CENIM), Spain, studied corrosion control by autonomous self-healing epoxy coatings based on superabsorbent healing agents.
Metal corrosion is a dangerous and expensive problem, and a common solution is the use of a thin protective polymer layer or coating. However, coatings can develop cracks, resulting in exposing the metal surface to the environment, requiring costly repair or replacement. Therefore, there is growing interest in developing self-healing polymer coatings capable of repairing microscale damage with minimal or no external intervention.
Published in Progress in Organic Coatings, the Spanish researchers presented an autonomous self-healing polymer coating based on an epoxy resin and superabsorbent polymer (SAP) blend as an anticorrosion coating. They manufactured tailor-made coatings by controlling the location of the SAP on the surface, middle, and bottom of the coating. The corrosion behavior and self-healing process of the coatings were analyzed at the macro, micro, and sub-micro scales using Electrochemical Impedance Spectroscopy (EIS).
The SAP preferentially located at the bottom showed coating resistance values higher than 1 × 1011 Ωcm2 over 10 days of immersion with 3-point defects. This configuration provided the best anticorrosion performance, preventing coating delamination, and protecting the metal from corrosion after surface damage, indicating better barrier properties. The SAP enabled local repair of the crack when in contact with water, minimizing the diffusion of oxygen and electroactive species, which are responsible for the corrosion of a metal.
Image – Aggressive agents present in all types of atmospheres increase the metallic corrosion, which is a dangerous and extremely expensive problem. A common strategy to solve this issue is the use of a thin protective polymer layer or coating. Courtesy of: Peter H – Pixabay (symbol image).
For more information:
https://www.sciencedirect.com/science/article/abs/pii/S0300944023001960
