Supramolecularly Mediated Robust, Anti-Fatigue, and Strain-Sensitive Macromolecular Microsphere Composite Hydrogels

Hydrogels are increasingly investigated and applied in flexible electronic devices, but their practical applications are often restricted by the poor mechanical and limited anti-fatigue properties. This works reports an approach to robust, anti-fatigue, and strain-sensitive hydrogels by introducing macromolecular microsphere and mediating their supramolecular cross-linking points. A model network composed of sulfonated polystyrene (SPS) microspheres and poly(acrylamide-co-acrylic acid)/Fe3+ (poly(Am-co-AA)/Fe3+) is investigated. The resulting composite hydrogels have high tensile strength (4.29 MPa) and anti-fatigue property. More interestingly, such composite hydrogels have strain-dependent conductivity and can be applied in robust flexible strain sensors for monitoring various human motions. Overall, the hydrogels developed herein not only help to understand the enhancing mechanism of composite hydrogels, but also offer alternative materials for fabricating robust electronic devices.