Thin films of a self-assembling peptide on TiO2 and Au studied by NEXAFS, XPS and IR spectroscopies

EAK16 is a 16 amino acid peptide consisting of an alternation of polar and non-polar pending groups and of positively and negatively charged residues, that makes this material capable of self-assembling, producing an extended ordered structure. Thin films of EAK16 were prepared on TiO2, and An surfaces and investigated by surface-sensitive techniques such as XPS (X-ray photoelectron spectroscopy), NEXAFS (near edge X-ray absorption fine structure) and IR spectroscopies. XPS analysis allowed to check the chemical structure of the samples and to determine the film thickness. IR experiments yielded evidence of the beta-sheet conformation of the peptide backbone. Polarization dependent NEXAFS measurements allowed estimating the angle between the axis of the peptide backbone and the sample surface. (c) 2005 Elsevier B.V. All rights reserved.