Dresden 2014 – scientific programme

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BP: Fachverband Biologische Physik

BP 30: Biomaterials and Biopolymers I (joint CPP/BP)

BP 30.6: Talk

Wednesday, April 2, 2014, 16:45–17:00, ZEU 222

A theoretical study of intermolecular interactions in crystalline cellulose — •Johannes Hoja and Alexander F. Sax — Department of Chemistry, University of Graz, Graz, Austria

It is often claimed that cellulose I consists of sheets held together by van der Waals interactions and that each sheet consists of chains held together by hydrogen bonds. Since all weak intermolecular interactions consist of electrostatic, exchange, induction, and dispersion contributions we analyze in this study all intermolecular interactions in cellulose in terms of these four interaction contributions. It was shown that dispersion is crucial for the stabilization of alcohol dimers.[1] This justifies the use of a dispersionless density functional and an additional function that describes the dispersion contribution to the interaction energy for the investigation of the interactions in cellulose Iα, Iβ, and II. For a better understanding of the nature of hydrogen bonds between cellulose chains we investigate model systems of alcohol dimers containing a different number of hydrogen bonds. Especially we study how the dimer stability depends on the intermonomer distance and the topology of the hydrogen bonding networks. For these investigations we use symmetry-adapted perturbation theory based on DFT description of monomers [SAPT(DFT)]. We find that dispersion is not only responsible for the intersheet stabilization but also contributes significantly to the intrasheet interactions. This is in opposition to the general view that only electrostatic interactions are important for hydrogen bonding.

[1] Hoja et al., Chem. Eur. J., DOI: 10.1002/chem.201303528, in press.