Fabrication of mechanically robust urushiol-based polymer coatings with excellent self-healing property and hydrophobicity

It is of great significance yet challenging to develop functional polymer coatings possessing highly efficient self-healing performances and robust mechanical properties simultaneously. To this end, a novel strategy was proposed for the fabrication of self-healing urushiol-based coatings based on Diels-Alder (DA) bond. Natural urushiol was firstly modified by using epichlorohydrin and furfuryl alcohol, and then crosslinked by N,N′-(4,4′-methylenediphenyl) dimaleimide (BMI) via DA bond to obtain the thermally reversible and self-healing bio-based coating. The synthesized products were characterized, and their thermostabilities, physico-mechanical properties, thermal reversible and self-healing performances were investigated in detail. The results showed that the ratio of urushiol furan derivative to bismaleimide had a significant effect on the studied properties of the self-healing coatings. The self-healing efficiency, hardness, contact angle of the as-prepared coating after formulation optimization can reach 83.22 %, 5H and 109.6°, respectively. This work suggested that natural urushiol was a kind of potential excellent raw material for preparing self-healing coating, and also provided a simple and efficient way to fabricate bio-based self-healing coatings with robust hardness and good hydrophobic characteristic.