Dresden 2011 – scientific programme
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 11: Poster: New Instruments and Methods
CPP 11.3: Poster
Monday, March 14, 2011, 17:30–19:30, P2
Capability of specular reflection-absorption IR spectroscopy for qualitative and quantitative analysis of organic films on metal substrates — •Georg Mayr1,2, Sabine Hild2, and Michaela Schatzl1 — 1voestalpine Stahl GmbH Linz, voestalpine-Straße 3, 4020 Linz, Austria — 2Institute of Polymer Science, Altenbergerstraße 69, J.K. University, 4020 Linz, Austria
Specular IR-reflection-absorption spectroscopy is a convenient tool for analysis of thin films of weak absorbing materials applied to highly reflecting substrates, e.g. metals. It is readily applied for practical purposes such as the analysis of organic coatings on metal sheets. Reflection spectra exhibit peculiarities compared to transmission spectra, what becomes evident from the investigation of films with various thicknesses (2-20 micrometer). Total absorption is not observed due to surface reflection. Weak absorption bands could be evaluated quantitatively. At intense bands deviations from the transmission mode band shape occur. These special features of reflection spectra could be explained by the refractive index dispersion and the therewith connected change in reflectivity of the coating layer in the wavelength area of an absorption band combined with Lambert-Beer absorption within the organic film. Under consideration of the aforementioned effects the reflection technique is capable of quantitative investigations, e.g. evaluation of the amount of remaining reactive functions within thermoset coatings.