Structural Insights into Cellulose-Coated Oil in Water Emulsions

Abstract

Cellulose is a renewable biopolymer, abundant on Earth, with a multi-level supramolecular structure. There has been significant interest and advancement in utilizing natural cellulose to stabilize emulsions. In our research, we develop and examine oil in water emulsions surrounded by unmodified cellulose as microreactors for the process of transformation of cellulose into valuable chemicals such as biodiesel. This study presents morphological characterization of cellulose-coated emulsions that can be used for such purposes. Cryogenic-scanning electron microscopy imaging along with light microscopy and light scattering reveals a multi-layer inner structure: an oil core surrounded by a porous cellulose hydrogel shell, coated by an outer shell of regenerated cellulose. Measurements of small-angle X-ray scattering provide quantification of the nano-scale structure within the porous cellulose hydrogel inner shell of the emulsion particle. These characteristics are relevant to utilization of cellulose-coated emulsions in various applications such as controlled release and as hosts for enzymatic biotechnological reactions.