Fabrication of Textile-Based Dry Electrode and Analysis of Its Surface EMG Signal for Applying Smart Wear

Ag/AgCl hydrogel electrodes, which are wet electrodes, are generally used to acquire bio-signals non-invasively. Research concerning dry electrodes is ongoing due to the following limitations of wet electrodes: (1) skin irritation and disease when attached for a long time; (2) poor adhesion due to sweat; and (3) considerable cost due to disposable use. Accordingly, electrodes in film, embroidery, and knit forms were manufactured from conductive sheets and conductive yarns, which are typical textile-type dry electrode materials, using different manufacturing methods and conditions. The prepared electrodes were conducted to measure the morphology, surface resistance, skin-electrode impedance, EMG signal acquisition, and analysis. The conductive sheet type electrode exhibited a similar skin-impedance, noise, and muscle activation signal amplitude to the Ag/AgCl gel electrode due to the excellent adhesion and shape stabilization. Embroidery electrodes were manufactured based on two-dimension lock stitch (Em_LS) and three-dimension moss-stitch (Em_MS). More stable EMG signal acquisition than Em_LS was possible when manufactured with Em_MS. The knit electrode was manufactured with the typical structures of plain, purl, and interlock. Although it was possible to acquire EMG signals, considerable noise was generated as the shape and size of the electrodes were changed due to the stretch characteristics of the knit structure. Finally, the applicability of the textile-type dry electrode was confirmed by combining it with a wearable device. More stable and accurate EMG signal acquirement will be possible through more precise parameter control in the future.

Automated summary

Ag/AgCl hydrogel electrodes, which are wet electrodes, are commonly used for non-invasive bio-signal acquisition. However, due to limitations such as skin irritation, poor adhesion, and high cost, research on dry electrodes is ongoing. This study manufactured textile-type dry electrodes in film, embroidery, and knit forms, and compared their performance with wet electrodes. The results showed that the conductive sheet type electrode had similar performance to the wet electrode, while the embroidery electrodes manufactured with Em_MS had more stable EMG signal acquisition. The knit electrode, on the other hand, generated considerable noise due to the stretch characteristics of the knit structure. The study confirmed the applicability of textile-type dry electrodes and suggested the need for more precise parameter control in the future.