Engineered phytic acid-lignin networks: one-pot strategy toward stable, multifunctional bio-based materials

This study introduces a one-pot approach that covalently links phytic acid into the lignin network while preserving lignin's ability to self-assemble into nanoparticles. Using diepoxy reagent and ethyl levulinate as crosslinkers, covalent bonding was achieved and confirmed via lignin model compounds experiments. The resulting phytic acid-modified lignin exhibited promising self-extinguishing behavior, retained lignin's antioxidant activity (IC50 of 0.1 g/l), and could be converted into stable nanoparticles via solvent shifting, thus broadening the application portfolio. These self-assembled spherical phytic acid-modified lignin nanoparticles (P-LNPs) with an average size of 140 ± 5 nm demonstrated high surface charge of -64.5 mV at pH 7, efficient cationic pollutant adsorption (62.9 mg/g adsorption capacity achieved instantly), and antifogging properties. This work presents a stable lignin-phytic acid system that can be used directly or as aqueous dispersion of nanoparticles, enabling a variety of applications and establishing a scalable framework to transform lignin into a high-value platform material.