Pickering Emulsions via Interfacial Nanoparticle Complexation of Oppositely Charged Nanopolysaccharides

Siqi Huan*, Ya Zhu, Wenyang Xu, David Julian McClements, Long Bai*, Orlando J. Rojas*

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

32 Citations (Scopus)
105 Downloads (Pure)


We consider the variables relevant to adsorption of renewable nanoparticles and stabilization of multiphase systems, including the particle's hydrophilicity, electrostatic charge, axial aspect, and entanglement. Exploiting the complexation of two oppositely charged nanopolysaccharides, cellulose nanofibrils (CNFs) and nanochitin (NCh), we prepared CNF/NCh aqueous suspensions and identified the conditions for charge balance (turbidity and electrophoretic mobility titration). By adjusting the composition of CNF/NCh complexes, below and above net neutrality conditions, we produced sunflower oil-in-water Pickering emulsions with adjustable droplet diameters and stability against creaming and oiling-off. The adsorption of CNF/NCh complexes at the oil/water interface occurred with simultaneous partitioning (accumulation) of the CNF on the surface of the droplets in net negative or positive systems (below and above stochiometric charge balance relative to NCh). We further show that the morphology of the droplets and size distribution were preserved during storage for at least 6 months under ambient conditions. This long-term stability was held with a remarkable tolerance to changes in pH (e.g., 3-11) and ionic strength (e.g., 100-500 mM). The mechanism explaining these observations relates to the adsorption of the CNF in the complexes, counteracting the charge losses resulting from the deprotonation of NCh or charge screening. Overall, CNF/NCh complexes and the respective interfacial nanoparticle exchange greatly extend the conditions, favoring highly stable, green Pickering emulsions that offer potential in applications relevant to foodstuff, pharmaceutical, and cosmetic formulations.

Original languageEnglish
Pages (from-to)12581-12593
Number of pages13
JournalACS Applied Materials and Interfaces
Issue number10
Early online date3 Mar 2021
Publication statusPublished - 17 Mar 2021
MoE publication typeA1 Journal article-refereed


  • cellulose nanofibrils
  • food emulsions
  • interfacial adsorption
  • nanochitin
  • pH tolerance
  • Pickering emulsions
  • salt resistance


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