Water-reducible and self-healing acrylic coatings based on Diels-Alder reversible reaction

A novel aqueous coating based on Diels-Alder (DA) chemistry is presented. In such material, three peculiar features, namely optical transparency, self-healing ability and water-reducibility, are integrated. The thermalreversibility of the polymer network is achieved by crosslinking a random terpolymer of furfuryl methacrylate (FMA), methacrylic acid (MAA) and 2-ethyl-hexyl methacrylate (EHMA) with an aliphatic bismaleimide through a DA reaction between furan and maleimide moieties. The effectiveness of the thermal reversibility is proved by differential scanning calorimetry, solubility tests and multiple scratch-repair cycles. The adoption of an aliphatic bismaleimide as crosslinker imparts a great transparency and absence of color to the thermally responsive coating as assessed by UV-vis spectroscopy. Thanks to the presence of the carboxyl moiety in the MAA units, dispersion in water after neutralization is enabled, ensuring the production of a water-reducible coating systems with added functionalities.