Fig. 3

Diagram showing conductive hydrogels connected to a circuit with a lighted bulb (A-I) and schematic diagram of the hydrogel conductivity test (A-II); Nyquist plots (B-I) and conductivity histograms (B-II) of different conductive hydrogels; Microscopic morphology of a (C-I), g (C-II) and j (C-II) hydrogels (a–j are as follows: (a) GO-PAM (b) Hep₅-rGO-PAM (c) Hep₁₀-rGO-PAM (d) Hep₂₀-rGO-PAM (e) PDA_0.2-rGO-PAM (f) PDA_0.4-rGO-PAM (g) PDA_0.8-rGO-PAM (h) Hep₂₀-PDA_0.2-rGO-PAM (i) Hep₂₀-PDA_0.4-rGO-PAM (j) Hep₂₀-PDA_0.8-rGO-PAM); ΔR/R₀ and sensitivity of conductive hydrogels under compressive stress (D-I) and tensile strain (E-I); ΔR/R₀ for 5 cycles at different compressive stress (D-II) and tensile strains (E-II); ΔR/R₀ at 20% compressive strain (D-III) and 100% tensile strain for 50 cycles (E-III)