The stretchable carbon black-based strain fiber with a remarkable linearity in a wide sensing range

Ascribed to its wide sensing range, high sensitivity, and low stiffness to match target objects with complex 3D shapes, the stretchable strain sensor has shown its promising applications in various fields, ranging from healthcare, bodynet, and intelligent traffic system, to the robotic system. This paper presents a low-cost and straightforward fabrication technology for the stretchable strain fiber with the combined attributes of a wide sensing range, exceptional linearity, and high durability. The hybrid composite consisting of carbon black and silicone is utilized as the functional material to respond to the external mechanical deformation due to the piezoresistive effect. To address the remarkable hysteresis of the CB-silicone composites, the latex tubes with excellent mechanical robustness and a considerable accessible tensile strain are introduced as the outer supporting components. After injecting the conductive CB-silicone composite into these tubes, the stretchable strain fibers are successfully prepared. Notably, the stretchable strain sensor exhibits linearity (R² = 0.9854) in a wide sensing range (0–400%) and remarkable durability even after the 2500 cycles under 100% tension. Additionally, the potential of this stretchable strain fiber as the wearable strain sensor and the real-time feedback is demonstrated by detecting the body motion and the expansion devices.