Fig. 4: Anti-friction stretchable electrodes and circuits.

a Schematic illustration of soft electrodes for reliable human biosignal recording. b Optical image of ECG recording for a male volunteer upon strong cyclic rubbing by fabrics. The dashed white area indicates the soft electrodes position. c Optical image of EEG recording for a male volunteer upon strong cyclic rubbing by hairy scalp. d Comparison of recording ECG and EEG signals when using Au-RPU and Au-PDMS electrodes before and after cyclic frictions. The faint red area indicates the test data from Au-RPU electrodes, while the light gray area indicates the test data from Au-PDMS electrodes. The data before and after fricitons are labeled by red and blue color. e Reliable and high-quality EMG signals recorded by Au-RPU electrodes even after 1000 frictions on the human forearm. f Comparison of the SNR values recorded with Au-RPU electrodes before and after 500 and 1000 cyclic frictions. g Comparison of electrical impedance spectroscopy measurements between the human skin and commercial Ag/AgCl electrode, as-deposited Au-RPU electrode, and Au-RPU electrodes after 1000 frictions. h–k Optical image of the stretchable LED circuit based on patterned Au-based interconnecting wires with the line width of 2 mm on RPU substrate (h) for reliable operation when stretching (i), folding (j) and kneading (k). Data in (f) are presented as mean values ± SD, n = 3 independent samples.