Tough Supramolecular Hydrogels Crafted via Lignin-Induced Self-Assembly

Area of Science:

• Materials Science
• Polymer Chemistry
• Supramolecular Chemistry

Background:

• Supramolecular hydrogels assembled via non-covalent interactions often lack sufficient mechanical strength.
• Developing strategies for enhanced hydrogel strength through molecular engineering is crucial for broader applications.

Purpose of the Study:

• To engineer a super-tough supramolecular hydrogel with improved mechanical properties using lignosulfonate sodium (LS) and polyvinyl alcohol (PVA).
• To investigate the self-assembly mechanism and multifunctional capabilities of the developed hydrogel.

Main Methods:

• Gradual diffusion of lignosulfonate sodium (LS) into a polyvinyl alcohol (PVA) solution.
• Mechanical property testing (tensile strength, Young's modulus, toughness).
• Analysis of crystalline domain formation and hydrogel network structure using simulations and analytical techniques.

Main Results:

• The optimized hydrogel achieved a tensile strength of ≈20 MPa, Young's modulus of ≈14 MPa, and toughness of ≈50 MJ m⁻³.
• LS induced the formation and densification of strong crystalline domains, significantly enhancing the hydrogel's mechanical performance.
• The hydrogel exhibited excellent low-temperature stability (<-60 °C), antibacterial properties, and UV-blocking capabilities (≈100%).
• Demonstrated self-restructuring, 3D patterning, and local strength enhancement capabilities of the LS-PVA hydrogel.

Conclusions:

• A novel, super-tough supramolecular hydrogel was successfully fabricated using an eco-friendly and biocompatible LS-PVA system.
• The hydrogel's enhanced mechanical strength and multifunctional properties offer significant potential for applications in biomedicine, engineering materials, and forestry.
• The study highlights the versatility of LS as a component for advanced hydrogel platforms.