Dresden 2011 – scientific programme
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BP: Fachverband Biologische Physik
BP 29: Posters: Biopolymers \& Biomaterials
BP 29.12: Poster
Thursday, March 17, 2011, 17:15–20:00, P3
Measured and simulated valence band structure of cellulose and lignin — •Thomas Haensel1, Syed Imad-Uddin Ahmed1,2, and Markus Reinmöller1 — 1Institut für Physik and Institut für Mikro- und Nanotechnologien, TU Ilmenau, PF 100565, 98684 Ilmenau — 2Ostfalia University of Applied Sciences, 38302 Wolfenbüttel
The regenerative biopolymers cellulose and lignin are available in large quantities. This makes them attractive for technical applications. Cellulose is used, for e.g. in the paper and textile as well as medical industry and in modern electronic devices. In the latter case they are utilized in batteries and solar cells as chemically inert isolating materials. In comparison, lignin is a waste product of the paper industry and is mainly used as fuel in combustion processes. It is also used as a filler in polymer compounds and applications in electronic devices are also targeted. While the structure and chemical composition of cellulose and lignin are well established, the molecular orbitals and valence band structures, which are important for understanding the electric properties, have not been thoroughly investigated. In this contribution, X-ray photoelectron spectroscopy (XPS) measurements of cellulose and lignin are combined with density functional theory (DFT) calculations of the basic units from cellulose and lignin to analyze their orbital and valence band structures. In particular, a structure at about 6 to 8 eV therein is attributed to oxygen rather than to carbon, as reported in literature. The results further indicate a significant dependence of the electronic properties on cross-linking and chemical processes leading to polymerisation.