Enhanced Polymerization and Surface Hardness of Colloidal Siloxane Films via Electron Beam Irradiation

Electron beam (EB) curing is a foldable hard coating process and has attracted significant research attention in the field of flexible electronic devices. In this study, we report a method for enhancing material surface hardness with low-energy EB curing in a short time. The low-energy EB improved the coating hardness of films by inducing cross-linking polymerization of the silicon-containing monomer. The hardness of the cured coating layer was measured as 3 H using a pencil hardness tester, and the transparency of the coating was higher than 90%. Owing to a series of cross-linking reactions between Si-O-C and Si-OH groups under EB curing and the formation of Si-Si bonds, the cured layer exhibited remarkable durability in the 100000-flexible cycle test. Additionally, the natural oxidation of the C-O groups on the surface of the coating formed carboxyl groups that improved the hydrophilic properties of the coating layer. To the best of our knowledge, this is the first study to propose that the hardness of polyethylene terephthalate films can be improved using low-energy EBs to rapidly cure silicon-containing coatings. Our results provide a novel and commercially viable approach for improving the hardness of touch screens and foldable displays.