Artificial skin with fast and robust self-healing ability for durable intelligent protection of magnesium alloys

Abstract

Imitating the self-healing behavior of the skin of living organisms to damage, the artificial skin with fast and robust self-healing ability that can provide durable intelligent protection for magnesium alloys was elaborately designed and fabricated in this work. The as-prepared artificial skin has two-layers, and the thin bottom layer is a hydrothermal film composed of magnesium (hydr)oxides and the thick top layer is a uniform and compact polyethyleneimine (PEI) – polyacrylic acid (PAA) polymer film that was fabricated by layer-by-layer (LBL) assembly method. The artificial skin can heal the cuts of 25 μm–120 μm within 25 min under moist atmosphere even with high concentrations of aggressive Cl-. More importantly, the skin shows exceptional self-healing robustness to various severe damage (including repeated cutting/scratching, high temperature and organic-solvent immersion). The molecular dynamics method was used to simulate the dynamic self-healing process of the artificial skin, which elucidates that the self-healing mechanism of the as-prepared artificial skin is mainly related to the special reversible interaction among polymer molecules under humidity. This work may not only boost the application of magnesium alloys in harsh environments, but also provide a novel way for durable intelligent protection of metallic materials.