A comparative table for the preparation methods of lignin-based hydrogels.
| Method | Principle/Mechanism | Advantages | Limitations | Scalability | Applications | References |
|---|---|---|---|---|---|---|
| Interpenetrating Polymer Network (IPN/ semi-IPN) | Formation of two independent networks; lignin incorporated via physical interpenetrating or semi-IPN; free radical polymerization | Improves mechanical strength, toughness, and stability; multifunctional properties’ enhanced swelling behaviour | Multi-step synthesis; may require organic solvents | Moderate | Drug delivery, biomedical hydrogels, responsive materials | [26, 50] |
| Crosslinking copolymerization | Simultaneous polymerization of monomers with lignin acting as crosslinker | Simple method; cost-effective; high swelling and water retention; biodegradable material possible | Use of chemical crosslinkers and initiators may cause toxicity; less precise structure | High (industrial friendly) | Superabsorbent hydrogels, agriculture, wastewater treatment | [52, 54] |
| Crosslinking grafted lignin and monomers | Grafting functional monomers onto lignin backbone followed by crosslinking | Enhanced reactivity; stronger and more stable network; tunable properties; mild reaction conditions | Difficult to control grafting density; heterogeneity; reproducibility issues | Moderate | Biomedical materials, coatings, controlled drug release | [50, 55] |
| ATRP/RAFT (controlled radical polymerization) | Controlled/living radical polymerization using “graft-from” or “graft-onto” strategies for precise architecture | Excellent control over molecular weight, structure, and functionality; advanced material design | ATRP: requires metal catalysts (toxicity, purification); RAFT: requires special agents, longer time, higher cost | Low to moderate | Advanced drug delivery systems, smart hydrogels, sensors | [57–59] |
HK: Conceptualization, Visualization, Data curation, Writing—review & editing, Writing—original draft. Disha: Data curation, Writing—review & editing. KS: Data curation, Writing—review & editing. OS: Project administration, Supervision, Writing—review & editing. BS: Conceptualization, Investigation, Project administration, Supervision, Writing—review & editing. All authors read and approved the submitted version.
The authors declare that they have no conflicts of interest.
Not applicable.
Not applicable.
Not applicable.
Not applicable.
The authors would like to thank the Department of Pharmaceutical Sciences and Drug Research, Punjabi University, Patiala and Bioinformatics center (BIC) sponsored by Department of Biotechnology for providing a computational facility under the BIC (Bt/PR39876/Btis/137/7/2021), New Delhi, India. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
© The Author(s) 2026.
Open Exploration maintains a neutral stance on jurisdictional claims in published institutional affiliations and maps. All opinions expressed in this article are the personal views of the author(s) and do not represent the stance of the editorial team or the publisher.