How cellulose stretches: synergism between covalent and hydrogen bonding

Altaner, C. M., Thomas, L. H., Fernandes, A. N. and Jarvis, M. C. (2014) How cellulose stretches: synergism between covalent and hydrogen bonding. Biomacromolecules, 15(3), pp. 791-798. (doi: 10.1021/bm401616n)

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Publisher's URL: http://dx.doi.org/10.1021/bm401616n

Abstract

Cellulose is the most familiar and most abundant strong biopolymer, but the reasons for its outstanding mechanical performance are not well understood. Each glucose unit in a cellulose chain is joined to the next by a covalent C–O–C linkage flanked by two hydrogen bonds. This geometry suggests some form of cooperativity between covalent and hydrogen bonding. Using infrared spectroscopy and X-ray diffraction, we show that mechanical tension straightens out the zigzag conformation of the cellulose chain, with each glucose unit pivoting around a fulcrum at either end. Straightening the chain leads to a small increase in its length and is resisted by one of the flanking hydrogen bonds. This constitutes a simple form of molecular leverage with the covalent structure providing the fulcrum and gives the hydrogen bond an unexpectedly amplified effect on the tensile stiffness of the chain. The principle of molecular leverage can be directly applied to certain other carbohydrate polymers, including the animal polysaccharide chitin. Related but more complex effects are possible in some proteins and nucleic acids. The stiffening of cellulose by this mechanism is, however, in complete contrast to the way in which hydrogen bonding provides toughness combined with extensibility in protein materials like spider silk.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Fernandes, Ms Anwesha and Jarvis, Dr Michael and Altaner, Dr Clemens and Thomas, Dr Lynne
Authors: Altaner, C. M., Thomas, L. H., Fernandes, A. N., and Jarvis, M. C.
College/School:College of Science and Engineering > School of Chemistry
Journal Name:Biomacromolecules
Publisher:American Chemical Society
ISSN:1525-7797
ISSN (Online):1526-4602
Copyright Holders:Copyright © 2014 The Authors
First Published:First published in Biomacromolecules 15(3):791-798
Publisher Policy:Reproduced under a Creative Commons License

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
435511Supramolecular structure and performance of wood celluloseMichael JarvisEngineering & Physical Sciences Research Council (EPSRC)EP/E026583/1CHEM - CHEMISTRY