Engineering of Durable Antifog Thin Coatings on Plastic Films by UV-Curing of Proteinoid Prepolymers with PEG-Diacrylate Monomers

Fog formation on transparent surfaces constitutes a major challenge in several optical applications, such as plastic packaging, lenses, mirrors, and windshields. To overcome this problem, we prepared and characterized durable antifog thin coatings on plastic films such as polyethylene terephthalate (PET). Proteinoids are biocompatible random polymers made of alpha-amino acids by thermal step-growth polymerization. Proteinoid prepolymers were prepared by adding activated double bonds to proteinoids via the Michael addition reaction. A series of thin antifog cross-linked coatings were prepared by spreading on PET films with a Mayer rod various mixtures of the proteinoid prepolymers, polyethylene glycol diacrylate, and a photoinitiator, followed by UV-curing of the dried coatings. The antifog properties of the coatings were determined by the contact angle, roughness, haze, and gloss measurements, as well as hot and cold fog tests, to examine the optical properties of the films under fog formation conditions. Mechanical properties such as adhesion, robustness, and abrasion resistance of the antifog coatings were examined by tape, knife-scratch, and sandpaper abrasion tests. The effect of coating composition, wettability, and roughness on the antifog properties of the coated PET films was elucidated. The formula was optimized, and the corresponding UV-cured antifog cross-linked thin coating exhibited transparency with good adhesion and excellent durable antifog performance.