To solve the problem that smart wearable flexible sensors wide strain sensing range and high sensitivity is difficult to reconcile

this study employs the wet coaxial spinning method to one-step preparation of a ribbon fiber with a dual conductive network structure. Specifically

carbon nanotubes in the non-solvent-induced phase separation process diffused to the polyurethane

resulting in carbon nanotubes embedded in polyurethane to form a conductive network

which constitutes a dual conductive network with the conductive layer of the carbon nanotubes

and the polyurethane acts as a sheath to provide stretchability. This structure realizes a low initial resistance (387 Ω)

a wide strain sensing range (Sensing ε=425%) and a high sensitivity (ε=0-200%

GF=208.8; ε=200-425%，GF=1359.2)

and it can also be used as a flexible sensor with an essentially unchanged relative resistance after 12

500 repetitions from 0 to 20% strain. In addition

this flexible sensor has a temperature sensing function (TCR=-0.240%/°C) and corrosion and water washing resistance

which is promising for a wide range of applications such as wearable devices.