Tough Supramolecular Hydrogels Crafted via Lignin‐Induced Self‐Assembly

Abstract

AbstractSupramolecular hydrogels are typically assembled through weak non‐covalent interactions, posing a significant challenge in achieving ultra strength. Developing a higher strength based on molecular/nanoscale engineering concepts is a potential improvement strategy. Herein, a super‐tough supramolecular hydrogel is assembled by gradually diffusing lignosulfonate sodium (LS) into a polyvinyl alcohol (PVA) solution. Both simulations and analytical results indicate that the assembly and subsequent enhancement of the crosslinked network are primarily attributed to LS‐induced formation and gradual densification of strong crystalline domains within the hydrogel. The optimized hydrogel exhibits impressive mechanical properties with tensile strength of ≈20 MPa, Young's modulus of ≈14 MPa, and toughness of ≈50 MJ m⁻3, making it the strongest lignin‐PVA/polymer hydrogel known so far. Moreover, LS provides the supramolecular hydrogel with excellent low‐temperature stability (<‐60 °C), antibacterial, and UV‐blocking capability (≈100%). Interestingly, the diffusion ability of LS is demonstrated for self‐restructuring damaged supramolecular hydrogel, achieving 3D patterning on hydrogel surfaces, and enhancing the local strength of the freeze‐thaw PVA hydrogel. The goal is to foster a versatile hydrogel platform by combining eco‐friendly LS with biocompatible PVA, paving the way for innovation and interdisciplinarity in biomedicine, engineering materials, and forestry science.