Fig. 2
Mechanical and electrical properties of the flexible device. a Tensile failure testing of carbon fiber with nano-copper and bare carbon fiber. The strain changed from 2.5 to 32.5%. The carbon fibers were all broken up at a strain of 32.5%. b The scattered points between ΔR/R0 and strain. The strain sensitivity of carbon fiber with nano-copper was 11.82 times than that of bare carbon fiber. c, d The dynamic resistance change of the device under the applied dynamic pressures. e The enlarged plot for showing resistance change when pressure changed from 0.35 to 0.40 kPa. f The bulged flexible device under pressure of 0.6 kPa. g The fitted curve between and pressure for calculating sensitivity and linear ship (sample number = 4). h Differential pulse voltammetry (DPV) for evaluating the stored charge ability of carbon fiber with nano-copper. i Fourier transform for evaluating the anti-noise ability of carbon fiber with nano-copper