Stretchable, adhesive and self-healing conductive hydrogels based on PEDOT:PSS-stabilized liquid metals for human motion detection

Conductive hydrogels have received extensive research interest in different application scenarios such as electronic skin, intelligent robotics and health monitoring. However, fabrication of competent conductive hydrogels with high sensing performance, self-healing and adhesion is still hard to achieve yet demanded. Here, we develop a series of novel conductive hydrogels by using poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS) to encapsulate liquid metal nanoparticles (LMNPs) in polyvinyl alcohol (PVA) matrixes. Thanks to the participation of PEDOT:PSS in polymeric network, the obtained LMNP-PEDOT:PSS-PVA (LMPP) hydrogels exhibit enhanced tensile strength (0.08 MPa), resilience and high conductivity (4.85 S/m). Besides, the introduction of PEDOT:PSS greatly stabilizes and enriches the LMNP-based conductive paths, therefore improving the strain sensing performance of hydrogels. More intriguingly, the LMPP hydrogels own excellent self-healing and adhesive properties due to the abundance of reversible bonds and functional groups within polymeric network. Leveraging these merits, such LMPP hydrogels can be applied as competent wearable devices for tracking various human motions in real-time, including joint movements and facial expressions. This work offers a new strategy for stabilizing LMNPs in polymeric network, which will contribute to the development of multifunctional conductive hydrogels.