(718a) Cellulose Nanofibril-Based High Internal Phase Pickering Emulsions and Derived Cellulose Foams

Cellulose nanofibrils (CNFs), with their high surface area, amphiphilic nature, and exceptional mechanical properties, have emerged as effective stabilizers for Pickering emulsions. In this study, we report on the development of CNF-stabilized oil-in-water (O/W) high internal phase emulsions (HIPEs), with internal oil phase volume fractions exceeding 74%. The resulting HIPEs exhibited long-term stability with the droplet size up to 7 µm. Emulsion characteristics were systematically investigated by varying ultrasonication power, oil phase viscosity, and surface charge on CNF particles. Controlled drying processes, including freeze-thaw and solvent exchange, followed by ambient drying, were applied to convert the emulsions into lightweight and porous cellulose foams. The resulting foam’s microstructure resembled that of the O/W emulsion as a template. Structural and morphological analyses using scanning electron microscopy and BET surface analysis confirmed the successful templating and structural integrity of the CNF matrix. These foams exhibited high porosity, low density, and tunable mechanical properties, showing potential for applications such as thermal insulation and sustainable packaging.