One-Step Fabrication of a PEDOT:PSS-Integrated Stretchable, Elastic, and Adhesive Conductive Hydrogel for Wearable Soft Sensors

Conductive hydrogels are promising materials for wearable sensors due to the skin-like softness capable of conforming to body movements and the water-rich 3D network conducive to ion transport. However, conventional hydrogels often suffer from poor mechanical strength, insufficient elastic recoverability, and inferior on-demand adhesion, severely restricting their long-term durability in practical use. In this work, we present a facile strategy to tackle the challenge via in situ copolymerization of acrylamide (AM) and acrylic acid (AA) within a well-dispersed poly(3,4- ethylenedioxythiophene)- poly(styrenesulfonate) (PEDOT:PSS) colloidal solution. This one- step strategy simplifies the fabrication process and enables homogeneous integration of PEDOT:PSS into the hydrogel network. By tuning the content of PEDOT:PSS, the as-prepared hydrogel exhibits a wide spectrum of mechanical properties and interfacial adhesion behavior, which is most likely ascribed to the soft−rigid phase regulation of core–shell-like PEDOT:PSS nanoparticles and poly(AM-co-AA) in the hydrogel matrix. The well-balanced rigid–soft network structure can enable the hydrogel to simultaneously possess desirable mechanical properties, outstanding cyclic elastic stability, and superior interfacial adhesion reversibility. In addition, the incorporated PEDOT:PSS nanoparticles offer high electrical conductivity, which thus enhances the sensitivity of the hydrogel. Benefiting from these attributes, the hydrogel can serve as a motion-sensing device to accurately and reliably monitor various human motions from large-scale joint movements ( e.g., finger bending) to subtle physiological activities ( e.g., vocal cord vibration). As a proof of concept for human–machine interaction, the hydrogel sensor is attached to a human finger as a command sensor to remotely trigger a robotic arm for object grasping and releasing. This work provides useful insights into developing hydrogel-based multifunctional flexible electronics with applications in health monitoring, soft robotics, and actuation systems.