LAUSR

Current conductive polymers win wide applications in smart strain/stress sensors, bioinspired actuators, and wearable electronics. This paper investigates a novel strain sensor by using conductive polypyrrole (PPy) nanoparticles coated polyvinyl alcohol (PVA) fibers as matrix. The flexible, water-resistant PVA fibers are initially prepared by combined electrospinning and annealing techniques, and then are coated with PPy nanoparticles through in situ polymerization. The resultant PPy@PVA fibers exhibit stable, favorable electrical conductivities due to the uniform point-to-point connections among PPy nanoparticles, e.g. after three-time' polymerizations, the PPy@PVA3 fiber film presents a sheet resistance of ∼840 Ω/sq and a bulk conductivity of ∼32.1 mS/cm. Cyclic sensing tests reveal that, PPy@PVA sensors show linear relationships between the relative resistance variations and the applied strains, e.g. the linear deviation of PPy@PVA3 is only 0.9 % within 33 % strain. After long-term stretching/releasing cycles, the PPy@PVA sensor exhibits stable, durable, and reversible sensing behaviors, no evident "drift" is observed over 1,000 cycles (5,000 seconds). This article is protected by copyright. All rights reserved.