Lignin nanoparticle-stabilized pickering emulsion: Mechanism, influencing parameter, and emerging application

Pickering emulsions using solid particles as stabilizers have attracted considerable interest due to their unique properties, environmental protection, high stability, and cost-effectiveness. However, the current solid particles used as stabilizers have been unable to meet the demands for sustainable development. Lignin nanoparticles (LNPs) are nanoscale particles derived from lignin, a complex biopolymer found in the cell walls of woods and plants. In recent years, LNPs have been widely used to stabilize Pickering emulsions due to its abundance, nanometer size, large specific surface area, good wettability, non-toxicity, and biodegradability. In this review, we overview the recent advances in the LNP-stabilized Pickering emulsion and their applications in a wide spectrum of emerging fields. The structure, preparation, and safety of LNPs are briefly overviewed. Then, the stabilization mechanism of LNP-stabilized Pickering emulsion is introduced. Next, two types of LNP-stabilized Pickering emulsion (i.e., unmodified and modified LNPs), their influencing factors, and physiochemical properties are comprehensively discussed. The recent advances in the application of LNP-stabilized Pickering emulsions in five areas are subsequently outlined, i.e., i) nanocomposites, ii) two-phase catalysis, iii) biomedicine, iv) daily skincare products, and v) enhanced oil recovery. Finally, the prospects of LNP-stabilized Pickering emulsion in the aforementioned fields are proposed.