Self healable cathodic electrophoretic deposition coatings
Cathodic electrophoretic deposition (CED) coatings are inevitably scratched following their application in processes such as automotive finishing. Self-healing coatings possess the ability to repair micro-scale damage, thereby extending their service life and reducing maintenance costs. Now, a novel strategy was developed to synthesise room-temperature intrinsic self-healing CED coatings by inserting 2-aminophenyl disulfide (APDS) into the polymer chain of cationic waterborne polyurethane (CWPU). Emulsion films incorporating the disulfide (SCWPU) could self-heal at room temperature via dynamic disulfide bond exchange and hydrogen bonding interactions.
Test results showed that the self-healing abilities of SCWPU film were 97.2% at RT over 24 h and 96.5% at 37°C (body temperature) after 4 h. CED coatings (8 μm, 3H pencil hardness) prepared from SCWPU emulsion also displayed self-healing properties at room temperature.
The study has been published in Journal of Coatings Technology and Research, Volume 19, September 2022.