Viscoelastic-Mapping of Cellulose Nanofibrils Using Low-Total-Force Contact Resonance Force Microscopy (LTF-CRFM)

Kristen Hess, Jason Killgore, Ashutosh Mittal, Wil Srubar III

Research output: Contribution to journalArticlepeer-review

4 Scopus Citations


Low-total-force contact resonance force microscopy (LTF-CRFM), an atomic force microscopy method, is introduced as a non-destructive means to quantify the local viscoelastic loss tangent (tan δ) of supported cellulose nanofibrils (CNFs). The method limits static and dynamic forces during measurement to minimize substrate and geometry effects and to reduce the potential for stress-induced CNF damage. LTF-CRFM uses Brownian motion to achieve the thermally-limited lowest dynamic force, while approaching adhesive pull-off to achieve the low static force. LTF-CRFM measurements were shown to generate analyzable data without evidence of nonlinear artifacts and without damage to the CNF over static forces ranging from 11.6 to 84.6 nN. The measured tan δ of CNFs was 0.015 ± 0.0094, which is the first reported tan δ measurement of an isolated CNF. Finally, LTF-CRFM successfully mapped tan δ along the length of CNFs to determine that kink defects along the CNF do not impart a local viscoelastic property change at the spatial resolution of the measurement.

Original languageAmerican English
Pages (from-to)5493-5509
Number of pages17
Issue number10
StatePublished - 2022

Bibliographical note

Publisher Copyright:
© 2022, This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.

NREL Publication Number

  • NREL/JA-2800-83185


  • Brownian motion
  • cellulose nanofibril
  • contact resonance force microscopy
  • viscoelastic loss tangent


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