Characteristic of siloxane hybrid material cured by thiol-ene reaction and application to transparent composite film

Abstract

A cover window having a high flexibility, mechanical strength, and transparency is required in a flexible display. There is need for new materials having high flexibility and strength together since these properties are rarely compatible in general materials. In this reason, organic-inorganic hybrid material, which has flexibility through organic chain structure and high strength through inorganic mesh structure together, has been developed. Especially, the glass-fabric reinforced (GFR) composite film using a siloxane-based organic-inorganic hybrid material has high transparency and durability while enhancing the flexibility and mechanical properties of the hybrimer thorough the glass-fabric. Siloxane network, which is inorganic bond formed by sol-gel process, makes the hybrimer have high mechanical strength and thermal stability, and organic network makes hybrimer have flexibility. In this study, a siloxane based organic–inorganic hybrimer using thiol-ene reaction was developed, which has transparency, flexibility, and high mechanical strength. The organic-inorganic materials have high thermal stability and mechanical properties through siloxane networks formed by sol-gel process, and flexibility through organic chains formed by polymerization. Thiol-methacrylate hybrimer was fabricated by adding chemicals containing thiol groups, where the thiol-ene reaction forms thioether and increases polymerization degree. The hybrid materials having flexibility through thioether bond, and high strength and thermal stability through high polymerization degree were fabricated. The siloxane based hybrid materials cured by thiol-ene reaction were analyzed about mechanical properties, thermal stability, and thermomechanical properties and compared with methacrylate siloxane hybrimer. The siloxane hybrid material cured by thiol-ene reaction was combined with glass-fabric to be GFRHybrimer film for application of flexible cover window. The hard coating was applied on GFRHybrimer film for enhancement of surface hardness. The fabricated composite film was analyzed about mechanical properties, thermal stability, and transparency. In addition, folding test was conducted to confirm that the fabricated composite film has a flexibility and durability suitable for cover window.