Regensburg 2002 – wissenschaftliches Programm
SYPF 2.19: Poster
Donnerstag, 14. März 2002, 09:00–18:00, Poster B
Morphology and Properties of Thin Epoxy Films: Concurrence of Polymerization, Cristallization and Demixing — •Thomas Britz1, Jan Kristian Krüger1, Bernd Valeske2, and Wulff Possart2 — 1Fachbereich 7.2 Experimentalphysik, Universität des Saarlandes, Geb. 38, Postfach 151150, 66041 Saarbrücken — 2Fachbereich 8.15 Werkstoffwissenschaften und Fertigungstechnik, Universität des Saarlandes, Geb. 22, Postfach 151150, 66041 Saarbrücken
We prepared thin films of about 100nm thickness of the epoxy resin with the diglycidylether of bisphenol A (DGEBA) as prepolymer and diethylenetriamine (DETA) as curing agent by spincoating on an aluminium substrate. During the curing process a partial demixing of the two components occurs resulting in an accumulation of DETA molecules in the interface layer to the substrate as well as in DGEBA rich clusters. The chemical turnover of epoxy groups during the polymerization is about a factor of 2 lower than in the bulk material. AFM investigations of the cured films show a topological very disturbed surface. These surface properties will be discussed in terms of existing DGEBA nano-crystallites within the bulk of the film material. Investigating the films temperature-dependent by means of Brillouin spectroscopy, we found a remarkable depression of the glass transition temperature of about 100K compared with the bulk. Heating the thin films over room temperature for the first time, we observed in our Brillouin spectra the appearance of a new phonon line, which we relate to the melting of the DGEBA-nanocrystals.