Fabrication of Conductive Polypyrrole/Polyurethane Composite Fibers for Large Strain Sensing

A kind of flexible, conductive polypyrrole–coated polyurethane (PPy/PU) fibers was fabricated by controlled chemical polymerization and its strain sensing ability was evaluated. The as-prepared fibers possessed high conductivity with a maximum value of 10-1 (Ω•cm)-1, and highly elastic nature of the PU matrix. It is further found that dense PPy layer was covered uniformly onto PU fiber surface, and an interpenetrating interface and strong hydrogen bonding interaction could be observed, which greatly benefited their high structural stability. More importantly, the composite fibers exhibited a wide strain deformation range up to 250% and high strain sensitivity of over 20 (at the large strain of 50%), and good reversible resistance response on cyclic force loading, which would open a high opportunity for fabricating strain sensing material in large volume for future smart device applications.