WtF-Nano: One-Pot Dewatering and Water-Free Topochemical Modification of Nanocellulose in Ionic Liquids or γ-Valerolactone

Research output: Contribution to journalArticleScientificpeer-review


  • Tiina Laaksonen
  • Jussi K.J. Helminen
  • Laura Lemetti
  • Jesper Långbacka
  • Daniel Rico del Cerro
  • Michael Hummel
  • Ilari Filpponen
  • Antti H. Rantamäki
  • Tia Kakko
  • Marianna L. Kemell
  • Susanne K. Wiedmer
  • Sami Heikkinen
  • Ilkka Kilpeläinen
  • Alistair W.T. King

Research units

  • University of Helsinki
  • Auburn University


Ionic liquids are used to dewater a suspension of birch Kraft pulp cellulose nanofibrils (CNF) and as a medium for water-free topochemical modification of the nanocellulose (a process denoted as “WtF-Nano”). Acetylation was applied as a model reaction to investigate the degree of modification and scope of effective ionic liquid structures. Little difference in reactivity was observed when water was removed, after introduction of an ionic liquid or molecular co-solvent. However, the viscoelastic properties of the CNF suspended in two ionic liquids show that the more basic, but non-dissolving ionic liquid, allows for better solvation of the CNF. Vibrio fischeri bacterial tests show that all ionic liquids in this study were harmless. Scanning electron microscopy and wide-angle X-ray scattering on regenerated samples show that the acetylated CNF is still in a fibrillar form. 1 D and 2 D NMR analyses, after direct dissolution in a novel ionic liquid electrolyte solution, indicate that both cellulose and residual xylan on the surface of the nanofibrils reacts to give acetate esters.


Original languageEnglish
Pages (from-to)4879-4890
Number of pages12
Issue number24
Publication statusPublished - 22 Dec 2017
MoE publication typeA1 Journal article-refereed

    Research areas

  • acetylation, cellulose, ionic liquids, nanofibers, topochemistry

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