Self-Healing Paint (Polyfibroblast)

Organization: The Johns Hopkins University Applied Physics Laboratory
Year: 2016

Corrosion is one of the largest cost drivers for the Department of Defense systems. The most effective method for preventing rust is to paint the surface. Since coating damage is impossible to prevent, greater gains may be made by developing a self-healing paint that continues to prevent corrosion even after the coating has suffered damage. To this end, Self-Healing Paint (Polyfibroblast) is a powder that can be added to chemical agent resistance coating primers to confer self-healing properties without requiring reformulation, retraining or significant added cost. Polyfibroblast consists of alkylsilane-filled microcapsules and zinc powder.  When mechanically damaged, broken microcapsules release silane into the scratch, where it forms a water-repellant barrier layer on the exposed steel surface. The sacrificial zinc in the primer provides short-term protection to the exposed steel from corrosion through cathodic polarization, providing sufficient time for the silane to form an effective barrier layer. Part of the barrier layer also forms on the zinc, thereby slowing down its rate of sacrifice, and thus extending the lifetime of galvanic protection.