Insights into the EDC-mediated PEGylation of cellulose nanofibrils and their colloidal stability. (1st February 2018)

• Record Type: Journal Article
• Authors: Kaldéus, Tahani; Nordenström, Malin; Carlmark, Anna; Wågberg, Lars; Malmström, Eva
• Is Part Of: Carbohydrate polymers. Volume 181(2018)
• Page Start: 871
• Page End: 878
• Publication Date: 2018-02-01
• Subjects: Cellulose nanofibrils -- PEGylation -- Steric stabilization -- Colloidal stability; Polysaccharides -- Periodicals; Polysaccharides -- Periodicals; Polysaccharides -- Périodiques; Electronic journals; 547.78
• DOI: 10.1016/j.carbpol.2017.11.065
• Languages: English
• ISSNs: 0144-8617

Abstract

Highlights: TEMPO-CNF has been directly sterically stabilized with PEG using NHS/EDC-coupling. An optimized coupling protocol was developed for a high PEGylation efficiency. A low degree of PEGylation (1%) is sufficient to improve the colloidal stability. Abstract: EDC-mediated coupling has frequently been utilized to poly(ethylene glycol) functionalize (PEGylate) cellulose-based materials, but no work has previously been reported on the direct N -(3-dimethylaminopropyl)- N -ethylcarbodiimide (EDC)-mediated PEGylation of cellulose nanofibrils (CNF). Herein, we report the first study where CNF has been directly sterically stabilized with amine-terminated PEG employing N -hydroxysuccinimide (NHS)-assisted EDC-coupling. This work has shown that this coupling reaction is highly sensitive to the reaction conditions and purification procedures, and hence an optimized coupling protocol was developed in order to achieve a reaction yield. Elemental analysis of the nitrogen content also showed the successful PEGylation. It was also shown that a surprisingly low PEGylation (1%) is sufficient to significantly improve the colloidal stability of the PEGylated samples, which reached dispersion-arrested-state-transitions at higher concentrations than neat CNF. The colloidal stability was preserved with increasing ionic strength, when comparably long polymer chains were grafted, targeting only 1% PEGylation.