Fig. 4. Triboelectric fibers and textiles for wearable applications.
a Schematic of the thermal drawing of a microtextured soft fiber. b, c The recorded Voc and Qsc of a 6 cm × 6 cm textile made up of a long microtextured fiber, under the applied force of 25.5 N (7.1 kPa). d Demonstration of the fibers as self-powered sensors to monitor finger-bending conditions. e, f Photographs and the corresponding Voc of a triboelectric fiber-integrated sweater to extract energy from human arm swing. g Comparison of the voltage output of the textile before and after being washed in a laundry machine. The inset image shows a water-permeable protective sack with the textile placed in a household laundry machine. h–j Breathing monitoring with a self-powered triboelectric wearable sensor. The fiber features six embedded electrodes (h) and a microtextured surface (i) for improved performance. The fiber is fixed on a stretchable belt, which is worn around the torso (j). k The generated waveforms allow the quantitative assessment of breathing patterns. Scale bars: h 200 μm, i 10 μm.