Stretchable Ag/AgCl Nanowire Dry Electrodes for High-Quality Multimodal Bioelectronic Sensing

Figures

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  Figure 1. (a) Preparation of Ag/AgCl NW dry electrode, (b) scanning electron micrographs of Ag NW electrodes and Ag/AgCl NW electrodes, (c) photographs of Ag/AgCl NW electrode before and after tensile deformation, and (d) impedance of each electrode.

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  Figure 2. Multiple bioelectrical signal measurement methods: (a) electrode arrangement for different bioelectric signal measurements. Experimental setup and measurement site: (b) ECG measurement, (c) EMG measurement, and (d) EEG measurement.

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  Figure 3. ECG signal: (a) part of the full-length raw signal measured by the Ag/AgCl NW electrode and commercial pre−gelled wet electrode, (b) the identification of the ECG signal waveform measured by the Ag/AgCl NW electrode, and (c) the identification of the ECG signal waveform measured by the Ag/AgCl NW electrode with a 50% tensile strain.

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  Figure 4. Average FFT amplitudes of NN sequences of full-length ECG signals measured at each electrode: (a) Ag/AgCl NW dry electrode with commercial wet electrode; (b) Ag/AgCl NW dry electrode at 50% tensile strain with commercial wet electrode.

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  Figure 5. HRV parameters of ECG signals of random slices measured by each electrode: (a) Ag/AgCl NW dry electrode with commercial wet electrode, (b) Ag/AgCl NW dry electrode at 50% tensile strain, and commercial wet electrode.

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  Figure 6. EMG signals measured for each electrode: (a) Ag/AgCl NW dry electrode and commercial wet electrode, (b) Ag/AgCl NW dry electrode with 50% tensile strain and commercial wet electrode, (c) EMG signals measured for Ag/AgCl NW dry electrode with different grip strengths, and (d) Ag/AgCl NW dry electrode after 150% deformation by stretching with different grip strengths. Note that the mutant signal between the two red dashed lines is the EMG during grip.

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  Figure 7. Raw EEG signals measured at each electrode: (a) Ag/AgCl NW dry electrode and (b) Ag/AgCl NW dry electrode with 50% tensile strain. Short-time Fourier transform (STFT, left) results of EEG signals measured at each electrode and fast Fourier transform (FFT, right) results after slicing the EEG signals after opening: (c,d) commercial wet electrode, (e,f) both Ag/AgCl NW dry electrodes, and (g,h) the Ag/AgCl NW dry electrode with 50% tensile strain. Note that the blue dashed lines in (a,b) distinguish the EEG signals after the eyes were opened.

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  Figure 8. Comparison of signal-to-noise ratios of multiple bioelectric signals measured by different electrodes [4,12,30,31,32,33,34,35,36].