Viscoelastic Relaxation of Cellulose Nanocrystals in Fluids: Contributions of Microscopic Internal Motions to Flexibility

We report the viscoelastic relaxation mechanisms of cellulose nanocrystals (CNCs) dispersed individually in fluids. Linear viscoelasticity and flow birefringence of softwood and tunicate CNC/glycerol dispersions in the dilute regime were measured. The obtained results were then compared with molecul...

Full description

Saved in:
Bibliographic Details
Published in:Biomacromolecules 2020-02, Vol.21 (2), p.408-417
Main Authors: Tanaka, Reina, Kashiwagi, Yu, Okada, Yuki, Inoue, Tadashi
Format: Article
Language:English
Subjects:
Birefringence
Cellulose - chemistry
Glycerol - chemistry
Nanoparticles - chemistry
Temperature
Time Factors
Viscosity
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We report the viscoelastic relaxation mechanisms of cellulose nanocrystals (CNCs) dispersed individually in fluids. Linear viscoelasticity and flow birefringence of softwood and tunicate CNC/glycerol dispersions in the dilute regime were measured. The obtained results were then compared with molecular theories for the linear viscoelasticity of rigid rods and semiflexible rods at infinite dilution by taking length distributions of CNCs into account. Although CNCs are traditionally regarded as rigid Brownian rods, the viscoelastic relaxation was not explained solely by the rotational motions of rods. Alternatively, molecular theories for semiflexible rods well-described the viscoelastic behavior; the CNCs showed additional relaxation modes derived from microscopic internal motions including “tension” and “curvature”, which originated from the finite flexural rigidity. Birefringence relaxation of the CNCs was dominated by the rotational motions of rods. Length distribution functions of the CNCs were thus calculated from the birefringence relaxation and agreed well with their microscopy-determined histograms.
ISSN:1525-7797
1526-4602
DOI:10.1021/acs.biomac.9b00943