Fig. 4: Electrical performance testing of MPP sensors.

a Comparison graphs of stress sensitivity curves of the MPP sponge, MP sponge, and PP sponge. b Calculated pressure sensitivity of MPP sensors. c I-V curve with an MPP sponge at 40–80% strain. d Resistance response of the MPP sponge from 0–80% step strain. e Response/recovery time of MPP sensors at 40% rapid strain. f The sensitivity and pressure sensing range of the MPP sensors are compared with those of pressure sensors in the literature. g MPP sponge resistance signal at a compression rate of 10–50 mm/min. h Cyclic response test graph of the MPP sponge at different strains from 5–80%. i Long-term stability of the MPP sponge at 20% strain