Fabrication of milled cellulose particles-stabilized Pickering emulsions

Abstract

Pickering emulsions stabilized by milled cellulose particles of the sizes ranging from 38 nm to 671 nm, which were prepared from a simple organic solvent -free media-milling process using cellulose powders with original sizes of 10–90 μm, have been successfully fabricated. The milled cellulose particles maintained their original rod-like shapes after the milling process. However, a notable decrease in the crystallinity of milled cellulose particles with the increase of milling time was verified by using X-ray diffraction. The effects of milling time, initial cellulose concentrations and oil/water ratios on the droplet sizes and stability of cellulose particles-stabilized Pickering emulsions were investigated. The milled cellulose particles were irreversibly adsorbed at the oil/water interface and formed stable emulsions with droplet size between 40 and 60 μm, which exhibited good stability over one-month storage. Milled cellulose stabilized emulsions also exhibited good stability against a wide range of pH (3, 5, 7, 9) and salt conditions (0.1–100 mM) with slight change in the droplet sizes. The rheological tests indicated the formation of gel network in the emulsions, which further promoted the emulsion stability. As sustainable biomolecules without negative impact on environment, cellulose particles processed through media-milling open opportunities for developing environmentally friendly new materials for emulsion stabilization.