Surface corrosion protection designing of particulate electromagnetic material towards self-healable functional composite

The electromagnetic wave active carbonyl iron (CI) particles were susceptible to environmental damage leading to functionality loss. Polymeric network as surface coating layer of CI appeared to be useful for improving their anti-corrosion ability. It is also expected that the coating could bridge the particles and the polymer matrix when CI was applied in polymer composites so that the integrity can be promoted. In the present work, disulfide bond [-S-S-] and 2-ureido-4-pyrimidinone (UPy) containing monomers were adopted for formation of crosslinked protection layer (named EAU layer) of CI. The EAU layer significantly enhanced the electrochemical corrosion resistance of CI based on the results of impedance modulus (0.01 Hz), potentiodynamic polarization test, and long term (200 cycles) cyclic voltammetry test. The CI-EAU could also retain good microwave absorbing ability. It is also found that when CI-EAU was embedded in synthesized polyurethane with dynamic [-S-S-] bond and UPy moieties. The composite could achieve fast self-healing under laser irradiation in the presence of Mxene. Besides, the composite was recyclable and could move the cargo under magnetic field. This well-designed strategy holds great promise not only for effective corrosion protection of electromagnetic functional particles, but also for realization of stable and self-healable electromagnetic composites.