PU nanoweb-based textile electrode treated with single-walled carbon nanotube/silver nanowire and its application to ECG monitoring

This paper is a research on textile electrodes fabricated by applying single-walled carbon nanotube (SWCNT) and silver nanowire (AgNW) to polyurethane (PU) nanoweb for monitoring electrocardiography (ECG) signals. In order to impart electrical conductivity, PU nanoweb was treated with SWCNT and AgNW. The PU nanoweb was dipped into 15 g of SWCNT dispersion mixed with 5 g of AgNW dispersion, and it was also treated with heat post-treatment and ethanol pre-treatment for enhanced conductivity. The electrical properties were evaluated by electrical linear resistance and impedance. The tensile properties were measured by Instron. By using the treated specimens, the wearable textile sensors were fabricated and verified to properly act as ECG electrodes via wear-trials compared to the conventional ECG electrode. To compare the ECG signals between Ag/AgCl electrode and textile electrodes, morphology of waveforms was compared and statistical analysis was also conducted. The results of the electrical properties showed that specimens SA1-H, SA1-E, and SA1-HE was much lower than SA1, and especially, SA1-H showed the lowest resistance. It corresponded to the results of impedance that specimen SA1 had the highest and specimen SA1-H had the lowest value. The results of the tensile properties showed that specimen SA1-H had higher tensile strength and elongation at break than the untreated. And, the results of the wear-trials showed that specimen SA1-H had the performance for ECG signals monitoring regardless of rest/stress-states, age, sex, and BMI index of the participants. Thus, it confirmed that the wearable textile sensors fabricated by using the SWCNT/AgNW treated PU nanoweb was suitable for ECG monitoring. Based on the results, it should have approximately 10 Ω cm^-1 when applied as the ECG electrode for long-term bio-monitoring smart clothing.