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

James C. Courtenay, Susana M. Ramalhete, William J. Skuze, Rhea Soni, Yaroslav Z. Khimyak, Karen J. Edler, Janet L. Scott

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

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.
Original languageEnglish
Pages (from-to)255-263
Number of pages9
JournalSoft Matter
Volume14
Issue number2
Early online date11 Dec 2017
DOIs
Publication statusPublished - 1 Jan 2018

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Hydrogel
Neutron scattering
cellulose
Cellulose
Nuclear magnetic resonance spectroscopy
neutron scattering
nuclear magnetic resonance
Substitution reactions
substitutes
spectroscopy
Hydrogels
Rheology
rheology
low weight
shear thinning
Shear thinning
cross sections
gelation
Gelation
Relaxation time

ASJC Scopus subject areas

  • Chemistry(all)
  • Condensed Matter Physics

Cite this

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.; Edler, Karen J.; Scott, Janet L.

In: Soft Matter, Vol. 14, No. 2, 01.01.2018, p. 255-263.

Research output: Contribution to journalArticle

Courtenay, James C. ; Ramalhete, Susana M. ; Skuze, William J. ; Soni, Rhea ; Khimyak, Yaroslav Z. ; Edler, Karen J. ; Scott, Janet L. / Unravelling cationic cellulose nanofibril hydrogel structure: NMR spectroscopy and small angle neutron scattering analyses. In: Soft Matter. 2018 ; Vol. 14, No. 2. pp. 255-263.
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