All-in-one sandwich-like PVA/PEDOT:PSS/WPU electrodes with low impedance and high stretchability for ECG monitoring

Conductive hydrogels have attracted considerable attention due to the promising application of flexible bioelectrodes. However, these hydrogel flexible electrodes are prone to damage or aging and readily influenced by external conditions like temperature, pressure and humidity, making them difficult in correcting accuracy real-time signals. Hence, we proposes to prepare all-in-one sandwich-like PVA/PEDOT:PSS/WPU electrodes with low impedance and high stretchability. Inspired by the layered structure of human skin, We fabricated ECG electrodes with high mechanical properties and low contact impedance by succsessively coating PEDOT:PSS conductive layer and PVA adhesive layer on WPU aerogel, in which the WPU aerogels can provide good elasticity on one hand and effectively promote the integration of PEDOT:PSS on the other hand. Furthermore, the outside layer of PVA gives good biocompatibility and comfort feel to the human skin, leading to a significant reduction of skin-electrode impedance. The PVA/PEDOT:PSS/WPU electrodes change resistance by only 45 % at 30 % strain, its conductivity reaches 7.8S/m, the fracture strain is 300 %. The as-prepared electrodes can accurately monitor subtle physical movements when wearing on the human-body, such as vocal cord vibrations, while continuously, consistently and clearly collecting ECG signals. Therefore, multifunctional integrated hydrogels can show promising applications in ECG biosensors.