Durability Design and Construction Enhancement of Textile Electrode Shape on Analysis of Its Surface Electromyography Signal

Advances in textile materials research and the health sector have contributed significantly to the invention of various flexible, smart, conductive materials that serve as electrodes for continuous monitoring of human physiological signals, such as electrocardiogram (ECG), EEG, electromyography (EMG), etc. EMG is used to record and evaluate the electrophysiological activity of the human muscle. The surface EMG signals are generally measured with an Ag/AgCl gel electrode. Although a circle-shaped electrode is significantly used, there will be a chance of evidence that another shape may be preferred. Therefore, this study investigated the performance of different electrode shapes, such as circles, triangles, rectangles, and squares, from their sensitivity, stability, and range of the electrode developed from the coated conductive textile material. This acts as an alternative to conventional gel electrodes. The dry electrodes were developed using conductive carbon paint coated with cotton fabric. The area of the electrode is 3.75 cm
²
, where the area is maintained the same for all the shapes. The morphological structure of the material is analyzed using a scanning electron microscope (SEM). The dry electrode resistance for each shape is calculated from IV measurement. The resistance of triangle- and rectangle-shape dry electrode is slightly higher than that of the circle- and square-shaped dry electrode. Even though the triangle-shaped electrode has higher sensitivity than other shapes, the rectangle-shaped electrode shows more deviation in signal range, which is 0.7 to −0.3 mV, while the range of commercial electrodes is 0.1 to −0.2 mV. The circular and square-shaped dry electrode signals are quite similar and within the range of commercial electrodes with less sensitivity value. Further, the circular and square-shaped electrodes are analyzed with different sizes, and it is observed that the larger the surface area, the lower the resistance with reliable signal. The EMG signal acquisition without interconnection is also observed in this research.