Paper Number
SF11 

Session
Surfactants, Foams and Emulsions

Title
Rheology of pickering emulsions stabilized via cellulose-derived nanoparticles

Presentation Date and Time
October 11, 2022 (Tuesday) 11:10

Track / Room
Track 7 / Ontario

Authors (Click on name to view author profile)

  1. Sohail, Mariam (North Carolina State University, Chemical and Biomolecular Engineering)
  2. Husain, Rushan (North Carolina State University, Chemical and Biomolecular Engineering)
  3. Pirzada, Tahira (North Carolina State University, Chemical and Biomolecular Engineering)
  4. Khan, Saad A. (North Carolina State University, Chemical and Biomolecular Engineering)

Author and Affiliation Lines (in printed abstract book)
Mariam Sohail, Rushan Husain, Tahira Pirzada and Saad A. Khan
Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27606

Speaker / Presenter 
Sohail, Mariam

Keywords
biomaterials; colloids; emulsions

Text of Abstract
Use of biofriendly colloidal particles as pickering emulsifiers is a suitable route to produce surfactant free environmentally friendly emulsions. We report use of Cellulose Acetate (CA) nanoparticles for stabilizing oil water emulsions. CA is a widely used cellulose ester due to its ease of processing, biodegradability, and biocompatibility. The nanoparticles are produced from an easily scalable nanoprecipitation process and are used to stabilize a model oil/water system consisting of isopropyl palmitate and water. We probe the effect of CA concentration and the oil/water ratio on the emulsion rheology and stability. Stable emulsions are produced at concentrations as low as 0.5 wt. % CA. The emulsions display gel-like characteristics with both G’ and G’’ being independent of frequency. Yield stress is measured by the elastic stress method and increase in CA concentration results in higher emulsion yield stress. Microscopy analysis reveals that at higher CA concentration emulsion droplet size decreases producing a dense network of droplets dispersed in the continuous phase. Thus, microscopic morphological analysis is consistent with the rheology data wherein a higher CA concentration facilitates formation of stiffer, more stable network consisting of smaller dispersed droplets with higher yield stress. Furthermore, we have investigated the emulsion microstructure recovery after exposure to different shear stress levels. We envision the use of these emulsions in various value-added applications including food, agriculture and cosmetic industries. The stiffer high CA content emulsions hold promise as suitable ink material for 3d printing for food applications whereas the softer emulsions can be used as active loaded formulations for agriculture/skin-care applications.