Self-healing Polyurethane Coating Based on Porous Carbon/ni Hybrid Composites for Electromagnetic Wave Absorption

Developing a lightweight, effective, and durable electromagnetic wave (EMW) absorbing coating is still a challenge. Herein, a novel self-repairable polyurethane (PU)-disulfide (SS)/porous carbon (PC)/Ni coating is initially assembled. The heterogeneous PC/Ni filler is derived from inexpensive cation exchange resins. And the texture, porous structure, defect, and electron transport can be adjusted by simply adjusting the carbonization temperature. The PU-SS/PC/Ni-700 degrees C presents an optimal reflection loss (RL) of -45.8 dB at a low loading (10 wt%) in X-band thanks to enhancements in polarization relaxation, magnetic resonance, multiple reflection and scattering, surpassing most reported fillers. Meanwhile, the disulfide and hydrogen bonds in the PU-SS matrix are in charge of repairing the coating's cracks and EMW adsorption capacity together after damage. Specifically, RL can recover -41.1 dB, after sunlight irradiation for 120 s. In short, this work may offer valuable inspiration for the fabrication of lightweight, efficient, long-life, low-cost, and mass-produced EMW absorption coatings.