Regensburg 2002 – wissenschaftliches Programm
O 34.7: Vortrag
Donnerstag, 14. März 2002, 17:00–17:15, H45
The effect of molecular packing on the reaction of organic monomolecular films to electron irradiation — •Michael Zharnikov1, Stefan Frey1, Hai-Tao Rong1, Manfred Buck2, Karin Heister1, and Michael Grunze1 — 1Angewandte Physikalische Chemie, Universität Heidelberg, D-69120 Heidelberg — 2School of Chemistry, St Andrews University, St Andrews, KY16 9ST, United Kingdom
Self-assembled monolayers (SAMs) formed on Au(111) from biphenyl-substituted alkanethiols CH3(C6H4)2(CH2)nSH (BPn) exhibit odd-even changes in the packing density and the tilt angle of the biphenyl moieties with varying length of the aliphatic part. We have applied X-ray photoelectron spectroscopy, near-edge X-ray absorption fine structure spectroscopy, infrared absorption spectroscopy, and advanced contact angle measurements to study electron beam induced damage in these systems. Although the damage character in all investigated SAMs was found to be generally similar, the extent and rate of the observed changes exhibited a clear correlation with the packing density and orientation of the biphenyl moieties in the BPn SAMs: The densely packed films are noticeably more insensitive (in terms of the orientational order, irradiation-induced desorption, and anchoring to the substrate) towards electron irradiation than the loosely packed layers. Considering the potential applications of the aromatic SAMs as a lithographic resist or a template, the introduction of a short aliphatic chain in these molecules provides a simple and efficient way to tailor their reaction toward ionizing irradiation.