Chemical regulation of lignin spatial conformation for a multifunctional soft material with a novel energy dissipation mechanism

•An effective strategy for the creep of soft materials was creatively presented.•Hydrogel has great potential as a platform for multifunctional soft material.•The work has reference value for further synthesis of biomass-based composites. An eternal and important challenge for soft materials is the occurrence of creep behavior, meaning they cannot maintain original structure and shape under continuous or repeated external forces, which will seriously affect the service life and value of soft materials. In this work, the inspiration comes from the multi-level structure of wood cells in trees, which can absorb external forces through the transformation of macromolecular spatial conformation to prevent occurrence of irreversible deformation. The conformational evolution of lignin in different solvent environments is investigated by all-atom molecular dynamics (MD) simulations. Biomass macromolecule lignin with three-dimensional spatial structure is formed into polyurethane modified lignin by 1,6-diisocyanate in different solvent environments polymerisation reaction to regulate its molecular spatial conformation to meet the needs of energy dissipation mechanisms under different external forces. The creep behavior of obtained hydrogels can be effectively improved by the introduction of lignin molecules with precise regulation of spatial conformation. After 20 cycles of 500% stretching amplitude loading–unloading, the dissipation energy is still maintained at more than 95% of the first cycle, and compressive strength reaches more than 85% of the first cycle after 20 cycles of 60% compression amplitude loading–unloading. Furthermore, the obtained hydrogel exhibits strong antibacterial properties, stress sensing in harsh environments, and wound healing promoting properties. These findings break through the conventional notion that the energy dissipation mechanism of hydrogels depends on sacrificial bonds and are expected to expand the application potential of natural biomass macromolecules to a multifunctional hydrogel sensing platform.