University of Oulu

Ojala, J., Visanko, M., Laitinen, O., Österberg, M., Sirviö, J., Liimatainen, H. (2018) Emulsion Stabilization with Functionalized Cellulose Nanoparticles Fabricated Using Deep Eutectic Solvents. Molecules, 23 (11), 2765. doi:10.3390/molecules23112765

Emulsion stabilization with functionalized cellulose nanoparticles fabricated using deep eutectic solvents

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Author: Ojala, Jonna1; Visanko, Miikka1; Laitinen, Ossi1;
Organizations: 1Fibre and Particle Engineering Research Unit, University of Oulu, P.O. Box 4300, FI-90014 Oulu, Finland
2Department of Bioproducts and Biosystems, Aalto University, P.O. Box 16300, FI-00076 Aalto, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 4 MB)
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Language: English
Published: Multidisciplinary Digital Publishing Institute, 2018
Publish Date: 2019-03-04


In this experiment, the influence of the morphology and surface characteristics of cellulosic nanoparticles (i.e., cellulose nanocrystals [CNCs] and cellulose nanofibers [CNFs]) on oil-in-water (o/w) emulsion stabilization was studied using non-modified or functionalized nanoparticles obtained following deep eutectic solvent (DES) pre-treatments. The effect of the oil-to-water ratio (5, 10, and 20 wt.-% (weight percent) of oil), the type of nanoparticle, and the concentration of the particles (0.05–0.2 wt.-%) on the oil-droplet size (using laser diffractometry), o/w emulsion stability (via analytical centrifugation), and stabilization mechanisms (using field emission scanning electron microscopy with the model compound—i.e., polymerized styrene in water emulsions) were examined. All the cellulosic nanoparticles studied decreased the oil droplet size in emulsion (sizes varied from 22.5 µm to 8.9 µm, depending on the nanoparticle used). Efficient o/w emulsion stabilization against coalescence and an oil droplet-stabilizing web-like structure were obtained only, however, with surface-functionalized CNFs, which had a moderate hydrophilicity level. CNFs without surface functionalization did not prevent either the coalescence or the creaming of emulsions, probably due to the natural hydrophobicity of the nanoparticles and their instability in water. Moderately hydrophilic CNCs, on the other hand, distributed evenly and displayed good interaction with both dispersion phases. The rigid structure of CNCs meant, however, that voluminous web structures were not formed on the surface of oil droplets; they formed in flat, uniform layers instead. Consequently, emulsion stability was lower with CNCs, when compared with surface-functionalized CNFs. Tunable cellulose nanoparticles can be used in several applications such as in enhanced marine oil response.

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Series: Molecules
ISSN: 1420-3049
ISSN-E: 1420-3049
ISSN-L: 1420-3049
Volume: 23
Issue: 11
Article number: 2765
DOI: 10.3390/molecules23112765
Type of Publication: A1 Journal article – refereed
Field of Science: 215 Chemical engineering
221 Nanotechnology
116 Chemical sciences
Funding: This work was funded by the Academy of Finland (Grant number: 283187). In addition, the support of the Tauno Tönning Foundation, the Tiina and Antti Herlin Foundation and the Oulu University Scholarship Foundation is gratefully acknowledged.
Academy of Finland Grant Number: 283187
Detailed Information: 283187 (Academy of Finland Funding decision)
Copyright information: © 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (