A facile method combined with electroless nickel plating and carbonization to fabricate textured Ni-coated carbon tube for flexible strain sensor

High-sensitive textile sensor acts the key component of electronic wearable products. It is a challenge to low-cost fabricate flexible sensors that possess excellent response reliability. In this regard, we employ a facile method combined with electroless nickel plating and carbonization to fabricate textured Ni-coated carbon tube (Te-CNiT) electrode, used as sensitive material for resistive sensor. Results showed that active group on the cotton surface would facilitate the adsorption of Pd2+. The generated Pd particle served as catalytic center to catalyze the electroless nickel plating by means of core-sheath micronfiber yarn with weave structure. Moreover, the “core” layer is transited from plant fibre to amorphous carbon which attached to the inside of Ni tube after annealing at 300 °C for 1 h, as a result, Te-CNiT electrode was fabricated. Interestingly, the change relationship between the relative resistance and strain present a quadratic equation of one variable, more specifically, the dependent variable varies obviously with the independent variable due to the established of extra conductor resistance and contact resistance in the Te-CNiT under the action of strain. As expected, the developed sensor exhibited ultrahigh sensitivity with a detection limit of 0.3% and gauge factor of 359. It can be integrated with the human body to detect multiple tiny signals, such as body movement, vocal cord vibration and facial expression with low response/recovery time (0.06 s/0.04 s) and excellent stability (9000 cycles).