Facile strategy toward the development of a self-healing coating by electrospray method

Abstract

A self-healing anti-corrosion epoxy coating was prepared by the incorporation of dual capsule healing system. Microcapsules were prepared through the facile electrospray method by using Poly(styrene-co-acrylonitrile) polymer as shell material. Polyetheramine and Methylene diphenyl diisocyanate (MDI) based isocyanate prepolymer were utilized as core materials because of their high reactivity and low sensitivity in forming polyurea polymers. Scanning electron microscopy (sem) images confirmed the spherical morphology of the prepared microcapsules with average diameters of 0.93 ± 0.55 μm and 1.21 ± 0.68 μm for the encapsulated polyetheramine and isocyanate microcapsules, respectively. Moreover, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) results confirmed the successful encapsulation of both core materials with a high encapsulation yield (71% and 68% for Polyetheramine and MDI based isocyanate respectively). Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization technique were used to assess the effects of utilizing the aforementioned system on the intrinsic anti-corrosion barrier property (on pristine samples ) and the self-healing efficiency (after cross scratching) of the resulting smart coatings. The corrosion assessment results confirmed the self-healing performance of the incorporated capsules along with a high healing efficiency (85%) for the optimum microcapsule content.