CNT/PDMS Composite Flexible Dry Electrodesfor Long-Term ECG Monitoring

Abstract

We fabricated a carbon nanotube (CNT)/ polydimethylsiloxane (PDMS) composite-based dry ECG electrode that can be readily connected to conventional ECG devices, and showed its long-term wearable monitoring capability and robustness to motion and sweat. While the dispersion of CNTs in PDMS is challenging, we optimized the process to disperse untreated CNTs within PDMS by mechanical force only. The electrical and mechanical characteristics of the CNT/PDMS electrode were tested according to the concentration of CNTs and its thickness. The performances of ECG electrodes were evaluated by using 36 types of electrodes which were fabricated with different concentrations of CNTs, and with a differing diameter and thickness. The ECG signals were obtained by using electrodes of diverse sizes to observe the effects of motion and sweat, and the proposed electrode was shown to be robust to both factors. The CNT concentration and diameter of the electrodes were critical parameters in obtaining high-quality ECG signals. The electrode was shown to be biocompatible from the cytotoxicity test. A seven-day continuous wearability test showed that the quality of the ECG signal did not degrade over time, and skin reactions such as itching or erythema were not observed. This electrode could be used for the long-term measurement of other electrical biosignals for ubiquitous health monitoring including EMG, EEG, and ERG.

Graphene-clad textile electrodes for electrocardiogram monitoring

“…The materials and fabrication processes are similar for contact and non-contact type electrodes, except that the electronics need to be adjusted for each. Some demonstrations include, carbon-nanotube or metal nanoparticle doped polymeric sensors [2][3][4], micromachined flexible sensors [5], minimally invasive needle type electrodes [6][7][8], and capacitive non-contact sensors based on printed-circuit board technologies [9][10][11].…”

Flexible Graphene Electrodes for Prolonged Dynamic ECG Monitoring

“…Following the development of flexible and stretchable electronics, alternative electrodes that do not require electrolytic gel (referred to as active dry electrodes) have been reported by many groups [9,10,11,12,13,14,15,16]. Baek proposed flexible polymeric electrodes [9], and Lee developed a metallic material layer, carbon nanotube (CNT) and polydimethylsiloxane (PDMS) composite-based dry ECG electrode [10].…”

“…Baek proposed flexible polymeric electrodes [9], and Lee developed a metallic material layer, carbon nanotube (CNT) and polydimethylsiloxane (PDMS) composite-based dry ECG electrode [10]. Ruffini proposed a dry electrode based on multiwall CNT (MWCNTs) arrays to penetrate the patient’s outer skin cell layers and reduce the measurement noise [12].…”

Graphene-Enabled Electrodes for Electrocardiogram Monitoring

“…Due to interesting mechanical and electrical properties of carbon-based nanomaterials, carbon nanotubes (CNTs) are selected to disperse into the flexible polymer substrates to make a better conductive ECG electrode. Lee and his colleagues [11] fabricated a dry ECG electrode by dispersion of CNT into the PDMS layer to investigate the effects of CNT concentration and robustness to motion and sweat. Tests showed that there was no sign of signal degradation after continuously wearing the CNT/PDMS electrodes after exercise (in the presence of sweat), and for 7 days.…”