New Pickering Emulsions Stabilized by Bacterial Cellulose Nanocrystals

TLDR

Bacterial cellulose nanocrystals (BCNs) are elongated, low‑charge particles that form stable colloidal suspensions in water. We prepared oil‑in‑water Pickering emulsions using BCNs produced by hydrochloric acid hydrolysis of bacterial cellulose, and characterized them by SEM and droplet‑coverage analysis as a function of BCN concentration. BCNs stabilize hexadecane/water interfaces, yielding monodisperse ~4 µm droplets that remain stable for months; a 60 % surface‑coverage threshold produces highly stable, deformable droplets attributed to irreversible adsorption and a 2D particle network, underscoring the potential of sustainable, cellulose‑based emulsions for eco‑friendly materials.

Abstract

We studied oil in water Pickering emulsions stabilized by cellulose nanocrystals obtained by hydrochloric acid hydrolysis of bacterial cellulose. The resulting solid particles, called bacterial cellulose nanocrystals (BCNs), present an elongated shape and low surface charge density, forming a colloidal suspension in water. The BCNs produced proved to stabilize the hexadecane/water interface, promoting monodispersed oil in water droplets around 4 μm in diameter stable for several months. We characterized the emulsion and visualized the particles at the surface of the droplets by scanning electron microscopy (SEM) and calculated the droplet coverage by varying the BCN concentration in the aqueous phase. A 60% coverage limit has been defined, above which very stable, deformable droplets are obtained. The high stability of the more covered droplets was attributed to the particle irreversible adsorption associated with the formation of a 2D network. Due to the sustainability and low environmental impact of cellulose, the BCN based emulsions open opportunities for the development of environmentally friendly new materials.