The design of self-healing agents is a topic of important scientific interest for the development of high-performance materials for coating applications. Herein, two series of copolymers of 2-hydroxyethyl methacrylate (HEMA) with either the hydrophilic N,N-dimethylacrylamide (DMAM) or the epoxy group-bearing hydrophobic glycidyl methacrylate were synthesized and studied as potential self-healing agents of waterborne polyurethanes (WPU). The molar percentage of DMAM or GMA units in the P(HEMA-co-DMAMy) and P(HEMA-co-GMAy) copolymers varies from 0% up to 80%. WPU/polymer composites with a 10% w/w or 20% w/w copolymer content were prepared with the facile method of solution mixing. Thanks to the presence of P(HEMA-co-DMAMy) copolymers, WPU/P(HEMA-co-DMAMy) composite films exhibited surface hydrophilicity (water contact angle studies), and tendency for water uptake (water sorption kinetics studies). In contrast, the surfaces of the WPU/P(HEMA-co-GMAy) composites were less hydrophilic compared with the WPU/P(HEMA-co-DMAMy) ones. The room-temperature, water-mediated self-healing ability of these composites was investigated through addition of water drops on the damaged area. Both copolymer series exhibited healing abilities, with the hydrophilic P(HEMA-co-DMAMy) copolymers being more promising. This green healing procedure, in combination with the simple film fabrication process and simple healing triggering, makes these materials attractive for practical applications.

Smart self-healing polymer materials are breaking open new pathways in industry, minimizing waste, and enhancing the long-term reliability of applications. Moreover, when they possess anti-corrosive properties, they effectively protect surfaces from wear and corrosion, leading to improved and more robust products. In the present work, we develop a series of new self-healing polyurethane coatings activated by temperature, through the encapsulation of vegetable oils (VO), namely olive, soybean, and castor oil, in the core of polyurea microcapsules (VO-MCs). Using a green method, water-dispersible microcapsules were embedded in water-based polyurethane matrices. Both the self-healing ability and the anti-corrosive properties of the respective films were evaluated after mechanical damage. Encapsulation allowed for the direct release of VOs into the damaged area; subsequently, the temperature increase reduced the viscosity of the oils, facilitating their flow and diffusion into the damaged area and accelerating the healing process. Soybean oil and olive oil showed remarkable performance in terms of self-healing and high anti-corrosion ability for the polyurethane coatings, while castor oil showed a limited anti-corrosion effect but quite satisfactory effectiveness in terms of self-healing. Overall, the study highlights the potential of using encapsulated oils in environmentally friendly, active coatings with dual action: corrosion protection and self-repair of damage.