Highly stretchable and sensitive SBS/Gr/CNTs fibers with hierarchical structure for strain sensors

Most of the reported flexible strain sensors can only normally sense external stretch in a quite narrow working range and with low sensitivity. In order to overcome these drawbacks, elastomeric fiber based strain sensors incorporating graphene (Gr) and carbon nanotubes (CNTs) were initially fabricated via coaxial wet spinning. The solution etching method was employed for forming a 1D@2D@1D hierarchical structure, with pores and microcracks on fibers, to reconstruct their conductive networks. The solution etched fiber based strain sensors achieved a significant improvement in obtaining a high maximum gauge factor of 1667 and capability of working over a wide strain range (0–500%, approximately 31 times larger than that for the non-etched fiber). Furthermore, the strain sensor showed excellent durability over 10,000 tensile strain cycles. Finally, the based strain sensor was used to monitor physiological movements such as finger, elbow and knee bending with fast and accurate responses.