Synergistic Double-Layer Mechanochromic Polymers for Enhanced Strain Sensing and Emission Control

The development of mechanochromic polymers offers transformative potential for applications requiring real-time stress sensing and emission control. This study presents a novel double-layer polymer system that synergistically combines a high-quantum-yield fluorophore-based emissive layer and a perylene bisimide-derived optical filter layer to achieve exceptional mechanochromic performance. The emissive layer utilizes pyrene-functionalized polyolefins to produce a strain-induced fluorescence shift, while the optical filter modulates emission intensity through absorption and dilution effects upon deformation. Comprehensive optical and mechanical characterization reveals that the combination of poly(styrene-b-(ethylene-co-butylene)-b-styrene) (SEBS)-based filters with poly(ethylene-co-octene) functionalized with 1-Pyrenemethylamine (POE-g-AMP) emissive layers delivers the most pronounced strain-dependent fluorescence enhancement, achieving a 120% increase in emission intensity at 250% elongation. This work overcomes traditional limitations in mechanophore adoption by utilizing cost-effective materials and scalable processing techniques. The proposed system demonstrates sensitivity and versatility, paving the way for innovative applications in structural health monitoring, wearable sensors, and dynamic design materials.