Doping Styrene Butadiene Rubber with Eu³⁺-Induced Diblock Copolymer Nanoaggregates Enhances Mechanical Properties and Enables Stretching-Enhanced Luminescence

Luminescent rubber (LR) becomes significantly brighter after being stretched, making it significant for tensile-strain sensing applications. The process begins with the preparation of Eu3+-induced nano aggregates from a diblock copolymer of polystyrene and poly(acrylic acid) (PS-b-PAA) in a dioxane solution. These aggregates, known as EIPAs, are then blended into styrene–butadiene rubber (SBR) to create EIPA-doped luminescent rubber (EIPAs-SBR). The amount of EIPAs in the SBR affects the material’s thermal stability, mechanical properties, and photoluminescence. Notably, the luminescence intensity of the EIPAs-SBR increases by up to 500% when stretched. The rubber emits light at a wavelength of 615 nm and has a long luminescence lifetime of about 778.73 μs, which enhances its color richness. This stretching enhancement effect (SEE) highlights the potential of these materials for applications in strain sensing and flexible, wearable optical displays. Additionally, the EIPAs-SBR materials demonstrate robust mechanical qualities, with a tensile strength of about 1400%, and good thermal stability, with a decomposition temperature above 350 °C. Overall, the study presents a simple and eco-friendly method to incorporate high-performance luminescent agents into SBR, paving the way for developments in strain-sensing luminescent materials.