Processing-induced self-organised triboelectric interfaces enable event-responsive cementitious composites

Structural materials are commonly designed to bear loads passively, whereas sensing and energy-harvesting functions are typically implemented using externally attached devices that are vulnerable to damage and interfacial failure. Here we report a processing-induced strategy for forming self-organised triboelectric interfaces directly within fibre-reinforced cementitious composites during vibration-assisted casting. Through fresh-state flow, fibre migration, and grid-assisted interception, conductive and dielectric constituents assemble into local fibre-enriched contact regions, enabling intrinsic electromechanical transduction without post-fabrication assembly. Microstructural characterisation reveals local fibre enrichment and fibre-grid interweaving around the embedded coated grid, while first-principles calculations support the interfacial charge redistribution between polyvinyl alcohol and polytetrafluoroethylene. The composites retain high mechanical toughness while exhibiting stable electrical responses under low-frequency mechanical excitation, with signal amplitude scaling with load and contact configuration. After cracking, newly created internal interfaces continue to provide functional output, demonstrating damage-tolerant electromechanical activity. We further demonstrate an event-triggered sensing system in which the embedded interfaces serve as self-powered signal sources for wake-up and alert operations. This work establishes a processing-driven route for programming functional interfaces within structural materials and provides a basis for intrinsically responsive infrastructure components. The study shows that vibration-assisted casting forms fibre-polymer contacts inside a cementitious composite, enabling electrical signals after damage and a laboratory demonstration of event-triggered alerts.