Unravelling cationic cellulose nanofibril hydrogel structure: NMR spectroscopy and small angle neutron scattering analyses

Courtenay, James C., Ramalhete, Susana M., Skuze, William J., Soni, Rhea, Khimyak, Yaroslav Z. ORCID: https://orcid.org/0000-0003-0424-4128, Edler, Karen J. and Scott, Janet L. (2018) Unravelling cationic cellulose nanofibril hydrogel structure: NMR spectroscopy and small angle neutron scattering analyses. Soft Matter, 14 (2). pp. 255-263. ISSN 1744-683X

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Stiff, elastic, viscous shear thinning aqueous gels are formed upon dispersion of low weight percent concentrations of cationically modified cellulose nanofibrils (CCNF) in water. CCNF hydrogels produced from cellulose modified with glycidyltrimethylammonium chloride, with degree of substitution (DS) in the range 10.6(3)–23.0(9)%, were characterised using NMR spectroscopy, rheology and small angle neutron scattering (SANS) to probe the fundamental form and dimensions of the CCNF and to reveal interfibrillar interactions leading to gelation. As DS increased CCNF became more rigid as evidenced by longer Kuhn lengths, 18–30 nm, derived from fitting of SANS data to an elliptical cross-section, cylinder model. Furthermore, apparent changes in CCNF cross-section dimensions suggested an “unravelling” of initially twisted fibrils into more flattened ribbon-like forms. Increases in elastic modulus (7.9–62.5 Pa) were detected with increased DS and 1H solution-state NMR T1 relaxation times of the introduced surface –N+(CH3)3 groups were found to be longer in hydrogels with lower DS, reflecting the greater flexibility of the low DS CCNF. This is the first time that such correlation between DS and fibrillar form and stiffness has been reported for these potentially useful rheology modifiers derived from renewable cellulose.

Item Type: Article
Uncontrolled Keywords: sdg 7 - affordable and clean energy ,/dk/atira/pure/sustainabledevelopmentgoals/affordable_and_clean_energy
Faculty \ School: Faculty of Science > School of Pharmacy
UEA Research Groups: Faculty of Science > Research Groups > Pharmaceutical Materials and Soft Matter
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Depositing User: Pure Connector
Date Deposited: 04 Jan 2018 00:07
Last Modified: 22 Oct 2022 03:27
URI: https://ueaeprints.uea.ac.uk/id/eprint/65849
DOI: 10.1039/C7SM02113E


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