Fig. 3.

Mechanical properties of the flexible Cu mesh films. a ΔR/R₀ (ΔR is the change in resistance value, R₀ is the initial resistance) of Cu mesh films at different bending radius. Insets are the digital photographs of initial and bending states. b ΔR/R₀ of Cu mesh film during 1000 bending cycles at the bending radius of 4 mm. c ΔR/R₀ of Cu mesh films with different coverage ratios at varying tensile strain (ε). d ΔR/R₀ of Cu mesh films during 1,000 tensile cycles at different tensile strains. e OM images of a Cu mesh film under different stretching states