Sustainable Production of Stable Lignin Nanoparticle-Stabilized Pickering Emulsions via Cellulose Nanofibril-Induced Depletion Effect

Sphericallignin nanoparticles (SLNs) are able to formulate Pickeringemulsions with various applications. However, SLN-stabilized emulsionscommonly comprise droplets in the micron range, resulting in inevitableinstability upon storage. Herein, nonadsorbing cellulose nanofibrils(CNF) are shown to induce stabilization of the diluted SLN-stabilizedPickering emulsions via concentration-dependent depletion effects.Two regimes for such depletion interactions are established, includingdepletion flocculation-induced droplet aggregation at intermediateCNF concentrations and depletion stabilization of micron-sized dropletsover critical CNF concentrations (0.2 wt %). The long-term stabilityof the SLN-based emulsions against creaming is over two months. Theuniversality of the findings is tested with different initial oilvolume fractions and droplet diameters. Overall, this study unveilsthe depletion effects in SLN-stabilized Pickering emulsions inducedby renewable CNF, offering a simple, sustainable route for tailoringtheir phase behavior and creating ultrastable systems that are availablefor formulating green products. Thisstudy unveils depletion effects induced by cellulosenanofibrils in lignin nanoparticle-based Pickering emulsions, offeringa sustainable route for creating an ultrastable system.