@Article{icces.2023.09608,
AUTHOR = {Rongzhuang Song},
TITLE = {Nanomechanics of Incipient Kink Defects Formed in Nanocellulose},
JOURNAL = {The International Conference on Computational \& Experimental Engineering and Sciences},
VOLUME = {27},
YEAR = {2023},
NUMBER = {2},
PAGES = {1--1},
URL = {http://www.techscience.com/icces/v27n2/54153},
ISSN = {1933-2815},
ABSTRACT = {Kink defects in nanocellulose are ubiquitous yet associated questions remain open regarding the unclear 
microstructure-mechanical property relationship. Various kink patterns without molecular-scale resolution 
result in bemusements of how nanocellulose forms different kinks and what the fundamental mechanisms 
of reversible and irreversible kinks are. In our atomic force microscopy images of mechanically treated 
cellulose nanofibrils, bent nanofibrils usually exhibit small curvatures while kinked nanofibrils feature 
sharp bends, in which kinks are conspicuous due to their promiscuous configurations. To identify the 
nanomechanics of incipient kink defects formed in nanocellulose, molecular dynamics simulations of 
cellulose nanocrystals (CNCs) under curvature-dependent bending are subsequently carried out. Four 
typical bending/kinking modes are found, depending on the anisotropic microstructure and size of CNCs. 
More importantly, two contrasting cases of kinks are demonstrated, providing evidence that kink defects in 
nanocellulose depend mainly on the microstructure at the molecular scale. Kinks in CNCs with the van der 
Waals interface are recoverable with a few residual defects. While kinks in CNCs with the hydrogen-bonding 
interface are irreversible with permanent microstructural damage due to the less ordered molecular chains 
and destroyed hydrogen-bonding network. Compressive stresses accumulated in the bottom chains of CNC 
contribute to the main mechanism to form incipient kinks in nanocellulose. Layer number is found to be the 
main size parameter dominating the bending/kinking of CNCs. Our experiments and simulations present 
intrinsic deformation mechanisms for reacquainting ubiquitous but mysterious kinks arising in 
nanocellulose, in which the distinctive insights should provide guidelines for cellulose-based biomass 
conversion and hierarchical material design with tailored properties.},
DOI = {10.32604/icces.2023.09608}
}