Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 42: Poster Session II (Nanostructures at surfaces: arrays; Nanostructures at surfaces: Dots, particles, clusters; Nanostructures at surfaces: Other; Nanostructures at surfaces: Wires, tubes; Metal substrates: Adsorption of O and/or H; Metal substrates: Clean surfaces; Metal substrates: Adsorption of organic/bio moledules; Metal substrates: Solid-liquid interfaces; Metal substrates: Adsorption of inorganic molecules; Metal substrates: Epitaxy and growth; Heterogeneous catalysis; Surface chemical reactions; Ab-initio approaches to excitations in condensed matter; Organic, polymeric, biomolecular films– also with adsorbates; Particles and clusters)
O 42.113: Poster
Mittwoch, 25. März 2009, 17:45–20:30, P2
Valence band spectroscopy on plasma trated wood surfaces — •Lothar Klarhöfer1, Evgenij Pachomow1, Sebastian Mathes1, Wolfgang Maus-Friedrichs1, and Wolfgang Viöl2 — 1Institut für Physik und Physikalische Technologien, Leibnizstraße 4, D-38678 Clausthal-Zellerfeld, Germany — 2HAWK FH Hildesheim/Holzminden/Göttingen, Fakultät Naturwissenschaften und Technik, Von-Ossietzky-Straße 99, 37085 Göttingen
Wood has been plasma treated using a dielectric barrier discharge at atmospheric pressure in ambient air, in order to improve the wettability of the surface. Chemical changes due to plasma treatment were studied by several surface sensitive techniques like XPS, UPS and MIES.
The functional groups of cellulose were identified in the valence band by fingerprints from glucose and cellobiose. The fingerprints for lignin were obtained by coniferyl alcohol, cinnamyl alcohol, phenol and benzene.
The plasma treatment in ambient air has different effects to the surface of cellulose and lignin respectively. An oxygen containing plasma reduces the cellulose surface, causes the loss of hydroxyl groups and the formation of C=O double bonds.
The lignin surface oxidizes in an oxygen containing plasma which leads to the removal of the hydrophobic phenyl groups, which react preferred with the plasma species. The destruction of the phenyl groups and therefore the molecule backbone causes the removal of the lignin from the surface, leaving a polar and rich on oxygen surface with goof wetting behaviour.