In order to explore the effect of pre-stretching treatment on the conductivity and sensing properties of polypyrrole elastic conductive filaments

polypyrrole-coated fibers with different weight gain ratios were obtained by pre-stretching the elastic filaments to different degrees during pyrrole polymerization. Its microscopic morphology was observed by scanning electron microscopy

and the electrical and sensing performances were tested and analyzed. The research results show that the resistance decreases with the increase of pre-stretch ratio (>70%). At 10% pre-stretch ratio

the polypyrrole layer is smoother

but has the best strain sensing performance: in the range of 0~2 cN

the internal sensitivity is high up to 7.68/N

and the sensitivity decreases and stabilizes at about 1/N after exceeding 2 cN. Both the repeatability experiment and the finger bending test show that the conductive filament pre-stretched by 10% has good sensitivity and sensing stability

and the resistance change rates are 24.71% and 11.01%

respectively. Therefore

the polypyrrole composite elastic filament with this structure is expected to be used in the detection of human motion and physiological signals. The elastic conductive yarns with higher pre-stretch ratios have a wrinkled structure on the surface

so they have the stable resistance value as stretched

which can be used in wires and electrodes.