Regulation of Lignin Microstructures to Construct Fully Biomass‐Based Elastomers for Large Crack Self‐Healing Artificial Muscles

Abstract Self‐healing elastomer‐based artificial muscle has attracted growing attention due to their potential applications in various fields. However, the development of self‐healing artificial muscles from biomass raw materials, capable of repairing large cracks at the millimeter scale remains a significant challenge. In this study, a novel lignin‐based all‐biomass elastomer is synthesized via a solvent‐free, one‐pot melting method. Thioctic acid (TA) undergoes ring‐opening copolymerization with itaconic acid (IA) at elevated temperatures, forming a flexible polymer matrix. Enzymatic hydrolysis lignin (EHL) achieves exceptional dispersion in molten TA, followed by in situ cross‐linking through metal coordination and hydrogen bonding. This resultant nano‐enhanced interlocking dual‐network structure endows the elastomer with high flexibility, stretchability, and self‐strengthening capabilities through mechanical training, closely mimicking the behavior of biological muscles. Most importantly, such an elastomer demonstrates remarkable shape memory function and intrinsic self‐healing ability, coupled with its photothermal properties, which facilitate the self‐repair of millimeter‐scale cracks. Thus, this study develops a novel strategy for lignin microstructure regulation and constructs a fully biomass‐based elastomer for millimeter‐scale self‐healing artificial muscle, which not only addresses the challenge of self‐healing scale but also achieves a breakthrough in the high‐value utilization of lignin.