Fluorescent self-healing waterborne polyurethane based on naphthalimide derivatives and its application in anti-counterfeiting

Waterborne polyurethane with high rigidity and self-healing properties plays an important role in polymer dyes and fluorescent anti-counterfeiting. In this paper, a naphthalimide derivative BHHNA-AM with high fluorescence and strong intermolecular hydrogen bonds was prepared and used as chain extender to synthesize a fluorescent waterborne polyurethane (PUAM). Intriguingly, the presence of highly rigid conjugate plane in molecules and strong non-covalent interaction between main chain and side chain amide group afforded PUAM film an autonomous self-healability at room temperature, the self-healing rate of scratched PUAM could be restored from 47.73% to 94.62% within 9 h, which could be widely used as thermoplastic adhesive. In addition, PUAM emulsion could be used as anti-counterfeiting ink printed on different substrates. After 14 days of UV irradiation and heat treatment, the color difference of printed products was less than 3.5, indicating excellent light resistance.