Deswelling of microfibril bundles in drying wood studied by small-angle neutron scattering and molecular dynamics

Aleksi Zitting*, Antti Paajanen, Lauri Rautkari, Paavo A. Penttilä

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Structural changes of cellulose microfibrils and microfibril bundles in unmodified spruce cell wall due to drying in air were investigated using time-resolved small-angle neutron scattering (SANS). The scattering analysis was supported with dynamic vapor sorption (DVS) measurements to quantify the macroscopic drying kinetics. Molecular dynamics (MD) simulations were carried out to aid in understanding the molecular-level wood-water interactions during drying. Both SANS experiments and simulations support the notion that individual cellulose microfibrils remain relatively unaffected by drying. There is, however, a significant decrease in fibril-to-fibril distances in microfibril bundles. Both scattering and DVS experiments showed two distinct drying regions: constant-rate drying and falling-rate drying. This was also supported by the MD simulation results. The shrinking of the fibril bundles starts at the boundary of these two regions, which is accompanied by a strong decrease in the diffusivity of water in between the microfibrils.

Original languageEnglish
Number of pages12
JournalCellulose
DOIs
Publication statusE-pub ahead of print - 26 Sep 2021
MoE publication typeA1 Journal article-refereed

Keywords

  • Cellulose microfibril
  • Drying kinetics
  • Moisture behavior
  • Molecular dynamics
  • Neutron scattering
  • Wood

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