Doping Styrene Butadiene\nRubber with Eu<sup>3+</sup>-Induced Diblock Copolymer Nanoaggregates\nEnhances Mechanical Properties\nand Enables Stretching-Enhanced Luminescence

Luminescent\nrubber (LR) becomes significantly brighter after being\nstretched, making it significant for tensile-strain sensing applications.\nThe process begins with the preparation of Eu<sup>3+</sup>-induced\nnano aggregates from a diblock copolymer of polystyrene and poly(acrylic\nacid) (PS-<i>b</i>-PAA) in a dioxane solution. These aggregates,\nknown as EIPAs, are then blended into styrene–butadiene rubber\n(SBR) to create EIPA-doped luminescent rubber (EIPAs-SBR). The amount\nof EIPAs in the SBR affects the material’s thermal stability,\nmechanical properties, and photoluminescence. Notably, the luminescence\nintensity of the EIPAs-SBR increases by up to 500% when stretched.\nThe rubber emits light at a wavelength of 615 nm and has a long luminescence\nlifetime of about 778.73 μs, which enhances its color richness.\nThis stretching enhancement effect (SEE) highlights the potential\nof these materials for applications in strain sensing and flexible,\nwearable optical displays. Additionally, the EIPAs-SBR materials demonstrate\nrobust mechanical qualities, with a tensile strength of about 1400%,\nand good thermal stability, with a decomposition temperature above\n350 °C. Overall, the study presents a simple and eco-friendly\nmethod to incorporate high-performance luminescent agents into SBR,\npaving the way for developments in strain-sensing luminescent materials.