Preparation of high-performance red fluorescent epoxy resin films guided by rare earth europium

Epoxy resins offer broad applications but are limited by their mechanical strength. This study enhances the properties of an indole-based epoxy resin (EPI) through the incorporation of europium ions (Eu 3+ ), leveraging their cation-π interactions. A red fluorescent indole-based epoxy resin (Eu@HEr) was synthesized, emitting at 616 nm under Ultraviolet (UV) light. Eu@HEr exhibited a 42% increase in tensile strength (86 MPa) and a 114% improvement in elongation at break (10.9%) compared to EPI. The thermal decomposition temperature of Eu@HEr rose by 64 °C, indicating superior thermal stability. These findings highlight the potential for high-performance epoxy resins with dual mechanical and luminescent properties.