Cellulose nanocrystals (CNCs) with
three different counterions
(H+, Na+, K+) were used to prepare
oil-in-water Pickering emulsions with and without salt; their stability
to coalescence and resistance to creaming were tested using two oil
types (high-polarity corn oil and superlow polarity hexadecane). Without
salt, only acid-form CNCs could stabilize corn oil emulsions, whereas
the salt-form Na+-CNCs and K+-CNCs failed. None
of the CNCs could stabilize hexadecane/water emulsions due to the
lack of oil-CNC interactions and strong repulsion between CNCs. However,
adding salt masked the differences between the CNC types, and all
CNCs could stabilize both corn oil and hexadecane emulsions. Unfortunately,
when salt was added, extensive creaming occurred owing to the water-phase
density increase and droplet aggregation. The effect of salt concentration
and neutralization of CNCs by different methods was also investigated.
This work highlights the complex nature of CNC interactions with salts,
oils, acids/bases, and other additives, which is relevant for envisioned
formulated products for food, cosmetic, and pharmaceutical applications
and reveals that the choice of CNC counterion does influence emulsion
performance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.