Textile Electronics for Long-Term Electrophysiological Signal Recording Application

Long-term electrophysiologic signal collecting is important since it provides a prior warning to people by detecting diseases such as heart failure or arrhythmia before the diseases progress to a more dangerous stage. It also provides fundamental data for training to improve performance by identifying the accurate amount of exercise and muscle usage for athletes. For this purpose, flexible and stretchable sensors have shown great potential for wearable and ambulatory electrocardiography signal monitoring applications. These soft sensors are comfortable, conform to human skin, and daily wearable in contradistinction to rigid metal-based conventional electronic devices. Nevertheless, most of long-term electrophysiologic sensors have focused on sticky dry electrodes for long-term signal collection because conformal contact of electrodes on the human skin can decrease contact impedance.<br/>Here, we propose an interesting approach for long-term electrophysiologic signal collecting electrode in dry condition by E-textile system. This system consists of textile and microfiber electrode that were coated by Poly(3,4-ethylenedioxythiophene) polystyrenesulfonate (PEDOT:PSS). For the textile electrode, PEDOT:PSS was simply printed on the nylon-based textile through screen printing manner and the stretchability of electrode was enhanced via polyethylene oxide (PEO) crosslinking process. In addition, hydrophobic treatment through 1H,1H,2H,2H-Perfluorooctyl-trichlorosilane (FTOS) effectively prevent water permeation that can cause erosion and dissolving of the electrode. Consequently, the textile electrode shows high durability in water. Moreover, the microfiber electrode offers greatly reduced contact impedance between skin and electrode, and improved signal-to-noise ratio (SNR) through dramatically increasing contact area. These electrodes combined via electrolyte conductive gel pad and build E-Textile system. Therefore, we achieve 1.1×10⁵ Ω×cm² contact impedance. In addition, the SNR of the electrocardiogram (ECG) and electromyography (EMG) SNR were 27 dB and 29 dB in dry atmosphere.