Theoretical and experimental studies of chitin nanocrystals treated with ionic liquid or deep eutectic solvent to afford nanochitosan sheets

Funes, Catalina Ferreira; Bouvier, Benjamin; Cezard, Christine; Fuentealba, Claudia; Jamali, Arash; Courty, Matthieu; Hadad, Caroline; Nhien, Albert Nguyen Van

Abstract

Chitin nanocrystals have gained growing interest due to their many excellent properties, however the higher crystallinity of these nano-rod-shaped particles is a major hindering factor in preparation of nanochitosans with low degree of acetylation (DA). Here we studied the effect of the ionic liquid 1- ethyl-3-methylimidazolium acetate (IL) and deep eutectic solvent (choline chloride:lactic acid) (DES) pretreatments of chitin nanocrystals (NCChits) before the deacetylation step using both experimental and theoretical approaches. The results showed that the ionic liquid pretreatment was able to partially disrupt the crystalline structure leading to a lower DA (18.2 %) after two cycles of deacetylation reaction. DES pretreatment, however, was unable to disturb the intra- and intermolecular hydrogen bonds, result- ing in a DA of 73.6 % similar to that of unpretreated chitin nanocrystals (73.2 %). SEM images of chitin nanocrystals pretreated with ionic liquid showed that the crystals can rearrange into sheets. Molecular simulations reveal the detailed mechanism of chitin nanocrystal dissociation, in which the combination of a net molecular charge and hydrogen-bonding groups on a single scaffold (as is the case for [C2mim] and [OAc]) plays a paramount role. These results can open the way to afford controlled nanochitosan sheets from chitin nanocrystals.(c) 2023 Elsevier B.V. All rights reserved.

Más información

Título según WOS: ID WOS:000997699700001 Not found in local WOS DB
Título de la Revista: JOURNAL OF MOLECULAR LIQUIDS
Volumen: 375
Editorial: ELSEVIER SCIENCE BV
Fecha de publicación: 2023
DOI:

10.1016/j.molliq.2023.121350

Notas: ISI