Figure 4. Mechanical and electrical characterization of the epidermis-bioinspired CurGONW-SMPS.
(a) Stress-strain curves of the CurGONW-SMPS for cyclic elastic recovery tests under various compression stress. (b) Stress-strain of the bioinspired CurGONW-SMPS under 1 kPa for the 1st and 1000th cycle. (c) The change in resistance under different compression rates with an applied pressure of 1 kPa. (d) Response time of the bioinspired CurGONW-SMPS. (e) The I-V curves of epidermis-bioinspired CurGONW-SMPS are made with the 800-grit sandpaper template. The linear correlation of voltage on current under varied pressures confirms the ohmic relationship between CurGONWs and spinosum microstructured substrate. (f) Sensitivity of the bioinspired piezoresistive sensor with varying loadings of CurGONWs (low, medium, high, very high). The one coated with a medium concentration of CurGONWs displayed a maximal sensitivity. (g) Sensitivity comparison of the bioinspired sensors fabricated using different surface roughness (400, 600, 800, and 1000). The sensor made with sandpaper no. 800 exhibits the highest sensitivity compared with those made with other roughness. (h) The representative resistance change for a step pressure from 0 to 15 kPa (from sandpaper no. 800). (i) Comparison of maximum sensitivity vs. maximum range with other published data[75-80]. (j) Cycling test of the bioinspired CurGONW-SMPS for around 1000 cycles at a constant pressure of 15 kPa. It confirms the excellent stability and durability of the bioinspired CurGONW-SMPS.