Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 17: Metal substrates: Adsorption of organic / bio molecules III
O 17.2: Vortrag
Montag, 14. März 2011, 17:30–17:45, TRE Phy
Direct formation of a polyamide on Ag(111): Joint XPS and STM studies — •Martin Schmid1, Christoph H. Schmitz2, Julian Ikonomov2, Hans-Peter Steinrück1, J. Michael Gottfried1, and Moritz Sokolowski2 — 1Lehrstuhl für Physikalische Chemie II, Universität Erlangen-Nürnberg — 2Institut für Physikalische und Theoretische Chemie, Universität Bonn
The polymer poly(p-phenylene terephthalamide) (PPTA) was synthesized on Ag(111) by co-adsorption of the reactive monomer compounds terephthaloyl chloride (TPC) and p-phenylenediamine (PPD) at 300 K. The resulting adsorbate phases were characterised by photoelectron spectroscopy (XPS) and scanning tunneling microscopy (STM). A detailed study of the chemical composition and morphology revealed a complex reaction mechanism, by which the formation of amide bonds leads to folded PPTA polymer chains. According to XPS, the chloride of the TPC precursor is not released as HCl as in the bulk reaction, but remains on the surface as chemisorbed Cl or AgCl. Further temperature-programmed XPS studies of pure TPC on Ag(111) reveal that the molecule decomposes already above 130 K, forming chemisorbed Cl (or AgCl) and a phenylene-dicarbonyl species, which is presumably stabilized by the substrate. The adsorbed chlorine partially desorbs above 800 K as molecular AgCl. Financial support by the Deutsche Forschungsgemeinschaft through SFB 624 and SFB 583 is gratefully acknowledged.