Transparent, Impact-Resistant Urethane-Siloxane Hybrid Coating with High Hardness and Exceptional Flexibility for Flexible Cover Windows

Highly impact-resistant transparent coatings, with a pencil hardness of 9H and an extremely small bending radius (r ≤ 1.5 mm), demonstrate significant potential as surface protection materials for ultrathin glass (UTG) cover windows in foldable displays. However, the inherent trade-offs between hardness and flexibility, as well as between hardness and impact resistance, pose a significant challenge in the development of such materials. To overcome these inherent conflicts, this study proposes a simple yet effective synergistic strategy for preparing urethane-siloxane hybrid coatings with the desired properties. The coating is a nanohybrid composite, prepared via photopolymerization, using methacrylate-functionalized polysilsesquioxane (MA-PSQ), 3-mercaptopropyl-functionalized polysilsesquioxane (MP-PSQ), and hexafunctional low-molecular-weight urethane acrylate (Hexa-UA).