Issue 18, 2021

Regioselective and water-assisted surface esterification of never-dried cellulose: nanofibers with adjustable surface energy

Abstract

A new regioselective route is introduced for surface modification of biological colloids in the presence of water. Taking the case of cellulose nanofibers (CNFs), we demonstrate a site-specific (93% selective) reaction between the primary surface hydroxyl groups (C6-OH) of cellulose and acyl imidazoles. CNFs bearing C6-acetyl and C6-isobutyryl groups, with a degree of substitution of up to 1 mmol g−1 are obtained upon surface esterification, affording CNFs of adjustable surface energy. The morphological and structural features of the nanofibers remain largely unaffected, but the regioselective surface reactions enable tailoring of their interfacial interactions, as demonstrated in oil/water Pickering emulsions. Our method precludes the need for drying or exchange with organic solvents for surface esterification, otherwise needed in the synthesis of esterified colloids and polysaccharides. Moreover, the method is well suited for application at high-solid content, opening the possibility for implementation in reactive extrusion and compounding. The proposed acylation is introduced as a sustainable approach that benefits from the presence of water and affords a high chemical substitution selectivity.

Graphical abstract: Regioselective and water-assisted surface esterification of never-dried cellulose: nanofibers with adjustable surface energy

Associated articles

Supplementary files

Article information

Article type
Paper
Submitted
28 Jun 2021
Accepted
29 Jul 2021
First published
02 Aug 2021
This article is Open Access
Creative Commons BY license

Green Chem., 2021,23, 6966-6974

Regioselective and water-assisted surface esterification of never-dried cellulose: nanofibers with adjustable surface energy

M. Beaumont, C. G. Otoni, B. D. Mattos, T. V. Koso, R. Abidnejad, B. Zhao, A. Kondor, A. W. T. King and O. J. Rojas, Green Chem., 2021, 23, 6966 DOI: 10.1039/D1GC02292J

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