Study on the Measurement Method of Skin Textile Electrodes Contact Impedance

Electrode-skin impedance is strongly influencing the quality of electrocardiograms (ECG) signals. Lower impedance results in stronger signals as well as less noise disturbance. In this study, we determine contact impedance between the skin and a flexible textile electrode based on a modified poly (3,4-ethylenedioxythiophene) :poly (styrenesulfonate) (PEDOT:PSS) coating, developed in our laboratory. Cotton knitted fabrics were used to test the measurement technique. For each measurement, a pair of same electrodes in terms of size was used. To obtain a better understanding of the obtained impedance results, the contact impedance was simulated by an electronic model and hence electrode circuit model components were calculated. In order to realize a comparative study, conventional medical electrodes silver/silver chlorides (Ag/ AgCl) were also assessed. The measurement technique can be applied to any other type of electrode in contact with a skin.