Sustainable production of lignin micro-/nano-particles (LMNPs) from biomass: Influence of the type of biomass on their self-assembly capability and physicochemical properties

The production of lignin micro-/nano-particles (LMNPs) has gained growing interest due to their eco-friendly feature and biological compatibility with negligible hazardous impacts. Herein, this work carefully addresses the preparation of LMNPs from different types of biomass, including pine wood, birch wood, pubescens, vinasse, corncob and corncob residue. Firstly, ligno-oligomers were produced from each biomass through a H₂O-THF co-solvent system. Then, LMNPs were generated from these effluents. Uniform and spherical LMNPs, consisting of benzene ring-stacked cores and hydrophilic shells, were obtained only from the liquids yielded by the treatment of the corncob residue and pine wood. The characterization of the ligno-oligomers and the LMNPs revealed that the molecular weights of the ligno-oligomers did not exert a significant effect on their self-assembly capability. The presence of guaiacyl units connected by β–O–4 and β–β linkages was beneficial for the π–π stacking of the benzene rings into compact cores, while the existence of β–5 linkages and C_α–oxidized side-chains exerted a negative effect. Stable and spherical LMNPs with an appropriate negative zeta potential and a relatively high thermal stability were obtained from the corncob residue and pine wood, which can serve as functional materials in various application areas.