Self-Healable, Low-Hysteresis, and Notch-Insensitive Conductive Hydrogels Enabled by Viscoelastic Nanoparticles for Sensitive Human Motion Sensing

Due to the conflicts between the extremely low hysteresis, toughness, and self-healing, it still remains challenging for the fabrication of hydrogels simultaneously achieving these contradictory properties. Here, we established a simple yet reliable strategy to produce tough, self-healable, and low-hysteresis conductive polymer hydrogels. The conductive hydrogels are fabricated via a one-step emulsion polymerization, which consists of the continuous acrylamide (AAm)/PEDOT:PSS aqueous phase and the dispersed n-butyl acrylate (nBA)/PEGBDB oil phase. In the formed hydrogel network, the PAAm polymer chains are covalently cross-linked by the special PnBA/PEGBDB viscoelastic nanoparticles, which play the following roles: (1) improving the hydrogel mechanical strength as cross-linker; (2) endowing the hydrogel with good self-healing capability via the dense boronic ester groups inside; and (3) transmitting the stress through the reversible deformation to significantly reduce the energy dissipation. The resultant PEDOT:PSS-based hydrogels display the combination of considerable stretchability, toughness, notch insensitivity, and extremely low hysteresis. Meanwhile, the fractured hydrogels can be healed at ambient temperature to restore their functionalities. This general yet versatile design strategy provides a solution to well balance the trade-off between the contradictory properties of toughness, self-healing, and low hysteresis and opens up new avenues for high-performance flexible electronic devices.