3D network PPy nanofibers for highly sensitive flexible piezoresistive pressure sensors

Polypyrrole (PPy) is extremely suitable for fabricating piezoresistive pressure sensors owing to its good biocompatibility and excellent electrical conductivity. However, the intrinsic rigidity and brittleness of dense PPy particles are difficult to form flexible conducting elastomers which hinder its further applications in wearable health monitoring systems. Herein, we report an efficient coaxial nanofibers network strategy to fabricate 3D conductive and elastic topological film through polydopamine (PDA)-assisted homogeneous deposition of PPy particles onto PVDF nanofibers (PVDF/PDA/PPy, PPP). It is noteworthy that dense PPy particles are difficult to lonely form flexible conducting film due to its rigid conjugated-ring backbone. However, PPy particles deposit on the surface of flexible PVDF/PDA nanofiber to form 3D network conducting films, which is both conductive and elastic, with the capable of withstanding large effective strains and stresses. Benefit from their unique 3D conducting network structures with more contact sites, the obtained sensors have superb sensitivity to the subtle pressure.