Anisotropic Muscle-like Conductive Composite Hydrogel Reinforced by Lignin and Cellulose Nanofibrils

Hydrogels with excellent mechanical properties and high conductivity are key materials for the development of flexible electronic devices, smart soft robots, and so forth. However, the preparation of high-performance conductive hydrogels remains a challenge. Enlightened by the strengthening mechanism of skeletal muscles, a green muscle-like conductive hydrogel was prepared through a repeated mechanical training process. Using cellulose nanofibrils (CNFs) as the fiber reinforcing source, partial depolymerized enzyme hydrolyzed lignin as the interfacial binding agent, and Ag⁺ as the conducting medium in a polyvinyl alcohol (PVA) matrix, the prepared composite hydrogel exhibited anisotropic high strength, high toughness, and excellent conductivity. Through the introduction of double physical enhancement networks and the adoption of a mechanical training method that mimics the muscle strengthening principle, the enhancement effect of CNFs was maximally demonstrated in the PVA composite hydrogel. Meanwhile, this study also provides a new and effective reference for the preparation of high-performance green hydrogels.