A nanowire assembly strategy for fabricating ultralight, resilient polypyrrole foams toward ultrasensitive pressure sensing.

The inherent rigidity of conducting polymer (CP) chains imposes severe limitations on their mechanical flexibility and processability and further constrains their utility in flexible pressure-sensing applications. Conventional fabrication strategies of CP-based flexible sensing materials commonly incorporate auxiliary elastomers or additives to improve the overall mechanical performance of devices. However, such operations frequently compromise sensing sensitivity or restrict the architecture to thin-film geometries, thus restricting the effective detection range. In this work, we developed a synthetic strategy for polypyrrole (PPY) foams via the synergistic interfacial assembly of nanowire oxidants and in situ oxidative polymerization. The resulting foams exhibit a biomimetic sponge-like architecture with hierarchical porosity, ultralight density (8 mg cm-3), and superior resilience. Piezoresistive sensors based on the PPY foams exhibit a sensitivity of 0.146 kPa-1 in the low-pressure range of 0-3 kPa and exceptional cyclic stability, enabling high-performance applications in human motion monitoring and spatial pressure analysis. This work provides an innovative structural design paradigm for CPs with a harmonious balance between ultralight characteristics and mechanical resilience, thereby opening avenues for next-generation wearable sensing platforms.