Cellulose Microfibril Twist, Mechanics, and Implication for Cellulose Biosynthesis

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• 作者：Zhen Zhao ; Oleg E. Shklyaev ; Abdolmajid Nili ; Mohamed Naseer Ali Mohamed ; James D. Kubicki ; Vincent H. Crespi ; Linghao Zhong
• 刊名：The Journal of Physical Chemistry A
• 出版年：2013
• 出版时间：March 28, 2013
• 年：2013
• 卷：117
• 期：12
• 页码：2580-2589
• 全文大小：598K
• 年卷期：v.117,no.12(March 28, 2013)
• ISSN：1520-5215

文摘

All-atom molecular dynamics simulations with explicit water solvent were used to investigate the microstructure and conformational dynamics of cellulose I尾 microfibrils as a function of microfibril length and cross-sectional size and shape. Cellulose microfibrils quickly develop a right-handed twist, which then remains stable over the entire 10 ns simulation time. The helical angle is independent of microfibril length and inversely proportional to its cross-sectional area, in accord with the expectations of continuum theory for an intrinsic chiral twist that is opposed by torsional shear. These calculations provide鈥攖o our knowledge鈥攖he first estimates of the shear modulus of a cellulose microfibril from MD simulations. The internal strains caused by this helical twist, propagated indefinitely along the microfibril axis, could be relaxed by periodic regions of amorphous structure along the axis of the cellulose microfibrils.