University of Oulu

Biomacromolecules 2023, 24, 9, 4113–4122,

Pickering emulsions and hydrophobized films of amphiphilic cellulose nanofibers synthesized in deep eutectic solvent

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Author: Qasim, Umair1; Suopajärvi, Terhi1; Sirviö, Juho Antti1;
Organizations: 1Fibre and Particle Engineering Research Unit, University of Oulu, Oulu 90570, Finland
2Laboratory of Natural Materials Technology, Åbo Akademi University, Turku 20500, Finland
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 12.7 MB)
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Language: English
Published: American Chemical Society, 2023
Publish Date: 2023-10-31


Herein, a dual-functioning deep eutectic solvent system based on triethylmethylammonium chloride and imidazole was harnessed as a swelling agent and a reaction medium for the esterification of cellulose with n-octyl succinic anhydride (OSA). The modified or amphiphilic cellulose nanofibers (ACNFs), synthesized using three different OSA-to-anhydroglucose unit molar ratios (0.5:1, ACNF-1; 1:1, ACNF-2; and 1.5:1, ACNF-3), were further converted into nanofibers with degree of substitution (DS) values of 0.24–0.66. The ACNFs possessed a lateral dimension of 4.24–9.22 nm and displayed surface activity due to the balance of hydrophobic and hydrophilic characteristics. The ACNFs made stable aqueous dispersions; however, the instability index of ACNF-3 (0.51) was higher than those of ACNF-1 (0.29) and ACNF-2 (0.33), which was attributed to the high DS-induced hydrophobicity, causing the instability in water. The amphiphilic nature of ACNFs promoted their performance as stabilizers in oil-in-water Pickering emulsions with average droplet sizes of 4.85 μm (ACNF-1) and 5.48 μm (ACNF-2). Self-standing films of ACNFs showed high contact angles for all the tested DS variants (97.48–114.12°), while their tensile strength was inversely related to DS values (ACNF-1: 115 MPa and ACNF-3: 49.5 MPa). Aqueous dispersions of ACNFs were also tested for coating fruits to increase their shelf life. Coatings improved their shelf life by decreasing oxygen contact and moisture loss.

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Series: Biomacromolecules
ISSN: 1525-7797
ISSN-E: 1526-4602
ISSN-L: 1525-7797
Volume: 24
Issue: 9
Pages: 4113 - 4122
DOI: 10.1021/acs.biomac.3c00472
Type of Publication: A1 Journal article – refereed
Field of Science: 216 Materials engineering
221 Nanotechnology
Funding: The research was conducted as a part of the Sustainable Binders and Coatings (SUSBINCO) project (No. 2447/31/2021) funded by the Bio&Circular Finland program of Business Finland.
Copyright information: © 2023 The Authors. Published by American Chemical Society. This publication is licensed under CC-BY 4.0.