Ms. Sana Ashqar - M.Sc. Candidate
25/10/2026
David Wang Auditorium, 3rd Floor, Dalia Maydan Bldg.
13:30
Detecting early damage before catastrophic failure occurs remains one of the toughest challenges in structural materials. Mechanophores offer a promising solution by turning mechanical stress into direct visual signals, yet their real-world use has been limited by low strain sensitivity in glassy polymers and a reliance on complex, substrate-specific chemistry. In this work, we address these challenges with a scalable, spiropyran-functionalized epoxy coating applied directly to aluminum substrates. Under deformation, coating fluorescence directly tracks the emergence of microstructural slip lines in the underlying metal. By tuning the network architecture, we achieved activation in three-point bending at 2.5% strain—right at the onset of plastic deformation. Introducing plasticizers allowed us to push this sensitivity further, activating the mechanophore at just 0.38% strain while simultaneously boosting coating ductility and toughness. Crucially, our analysis reveals that activation is not just a side effect of matrix softening; instead, effective plasticizers promote local chain alignment that concentrates mechanical stress directly onto the mechanophore. These insights provide practical design rules for force transduction in glassy polymers, pointing the way toward scalable smart coatings for early, non-destructive safety monitoring.