A transparent, abrasion-resistant anti-fog coating on polycarbonate substrates

Polycarbonate (PC) substrates are widely used in our daily lives, but their inherent hydrophobicity makes them susceptible to changes in ambient temperature and humidity, which can cause fog that affects their light transmittance, limiting their use in applications that require high light transmittance, such as eyeglass lenses, automotive parts, and medical devices. In this study, P(HEAA- co -AEMA- co -BPA) transparent anti-fog coatings were prepared via one-step free radical copolymerization using N -(2-hydroxyethyl)acrylamide (HEAA), 2-aminoethylmethacrylate hydrochloride (AEMA), and 4-acryloyloyloxybenzophenone (BPA) as monomers. The hydrophilic HEAA monomer provides the coating with anti-fogging performance. The amino functional group in the AEMA segment reacts with the ester group on the surface of the PC substrate to form covalent urethane bonds during heat curing, and the hydrophobic BPA not only covalently binds with the PC substrate under UV irradiation but also prevents the anti-fogging performance of the anti-fog coating from being lost because of the absorption of too much water. The resulting transparent coatings have excellent anti-fogging effects in hot vapor tests and freeze–warm tests. Furthermore, the coatings exhibited good adhesion in the cross-cut tests. Quartz sand abrasion tests and wet cloth wiping tests also revealed that the coating has good abrasion resistance in both dry and wet states.