Cooperative self-healing performance of shape memory polyurethane and Alodine-containing microcapsules

In this study, a method to prepare self-healing coatings by incorporating Alodine-containing microcapsules as fillers in Shape Memory Polyurethane (SMPU) was presented. Toluene diisocyanate (TDI) prepolymer was prepared for the microcapsule shells, while a healing agent (Alodine 5200) was selected for the core. SMPU with polyethylene glycol (PEG) as the soft segments and isophorone diisocyanate (IPDI) and 2,2-hydroxymethyl butyric acid (DMBA) as the hard segments were synthesized as main film-formers. A set of techniques including Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), electrochemical impedance spectroscopy (EIS), Scanning Kelvin Probe (SKP), and optical microscopy were used to completely characterize their self-healing performance on Al 7B04 T74 aluminum alloy surfaces. The study on the self-healing mechanism indicated that the self-healing process can be divided into two stages, and there was enormous potential for repairing large cracks with this technique.