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

Author(s)

Beaumont, Marco ^{[1, 2]} ; Otoni, Caio G. ^[3] ; Mattos, Bruno D. ^[1] ; Koso, Tetyana V. ^[4] ; Abidnejad, Roozbeh ^[1] ; Zhao, Bin ^[1] ; Kondor, Anett ^[5] ; King, Alistair W. T. ^[4] ; Rojas, Orlando J. ^{[6, 1, 7, 8]}

Affiliation

^[1] Aalto Univ, Sch Chem Engn, Dept Bioprod & Biosyst, POB 16300, FI-00076 Espoo - Finland

^[2] Univ Nat Resources & Life Sci Vienna BOKU, Inst Chem Renewable Resources, Dept Chem, Konrad Lorenz Str 24, A-3430 Tulln - Austria

^[3] Fed Univ Sao Carlos UFSCar, Dept Mat Engn DEMa, Rod Washington Luis, Km 235, BR-13565905 Sao Carlos, SP - Brazil

^[4] Univ Helsinki, Dept Chem, Mat Chem Div, Virtasen Aukio 1, FI-00560 Helsinki - Finland

^[5] Surface Measurement Syst Ltd, Rosemont Rd, London HA0 4PE - England

^[6] Univ British Columbia, Dept Chem & Biol Engn, 2360 East Mall, Vancouver, BC V6T 1Z3 - Canada

^[7] Univ British Columbia, Dept Wood Sci, 2424 Main Mall, Vancouver, BC V6T 1Z3 - Canada

^[8] Univ British Columbia, Dept Chem, 2036 Main Mall, Vancouver, BC V6T 1Z3 - Canada

• Document type: Journal article
• Source: GREEN CHEMISTRY; v. 23, n. 18 AUG 2021.
• Web of Science Citations: 2

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. (AU)

• FAPESP's process: 19/00370-9 - Multifunctional materials from nanochitin
• Grantee: Caio Gomide Otoni
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor
• FAPESP's process: 16/13926-7 - Multi-user equipment approved in grant 15/254065: LUMSizer
• Grantee: Watson Loh
• Support Opportunities: Multi-user Equipment Program