Cellulose https://doi.org/10.1007/s10570-021-04325-4 (0123456789().,-volV) ( 0123458697().,-volV)
REVIEW PAPER
Cellulose and the role of hydrogen bonds: not in charge of everything
Malin Wohlert . Tobias Benselfelt . Lars Wa˚gberg . Istva´n Furo´ . Lars A. Berglund . Jakob Wohlert
Received: 13 August 2021 / Accepted: 6 November 2021 The Author(s) 2021
Abstract In the cellulose scientific community, hydrogen bonding is often used as the explanation for a large variety of phenomena and properties related to cellulose and cellulose based materials. Yet, hydrogen bonding is just one of several molecular interactions and furthermore is both relatively weak and sensitive to the environment. In this review we present a comprehensive examination of the scientific literature in the area, with focus on theory and molecular simulation, and conclude that the relative importance of hydrogen bonding has been, and still is, frequently exaggerated.
Introduction and background
Consider a wet nanocellulose film that is rolled up and left to air dry, resulting in a nanopaper roll that is sufficiently stiff and wet-stable to be used as a drinking straw. No adhesives are used to seal the roll, but it nevertheless holds together. This mechanism is attributed to the formation of hydrogen bonds (H- bonds) between the nanopaper surfaces (Wang et al. 2020). But can this really be the full story? The year 2020 marked the 100-year anniversary of the H-bond concept (Gibb 2020; Pauling 1939), which has, since then, been central for explaining structure- property relationships in biological matter (Jeffrey and Saenger 1994), including cellulose. Starting with the discovery of nanocellulose and promises of a bright future as sustainable load-bearing component in high performance materials (Berglund and Peijs 2010; Ben´ıtez and Walther 2017), the last decade has seen an exponential growth of the interest in cellulose research. Rapid development in cellulose chemistry, processing and characterization has led to a property range of cellulose-based materials that expanded beyond imagination and to new areas of application that are continuously discovered. But where do all these intriguing and, indeed, extraordinary properties originate from? Although justified in some cases, there is a tendency in the cellulose field to invoke H-bonding as an almost magical explanation. For example, unique characteristics of cellulose such as high axial
Keywords
Cellulose Hydrogen bonding
Computer modeling Nanomaterials
M. Wohlert Division of Applied Mechanics, Department of Materials Science and Engineering, Uppsala University, Box 534, SE-751 21 Uppsala, Sweden T. Benselfelt L. Wa˚gberg L. A. Berglund J. Wohlert Department of Fiber and Polymer Technology, School of Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden L. Wa˚gberg I. Furo´ L. A. Berglund J. Wohlert ( & ) Wallenberg Wood Science Center, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden e-mail: jacke@kth.se I. Furo´ Department of Chemistry, School of Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden
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