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CP: Chemische Physik

CP 9: Symposium: Benetzung und dünne Filme

CP 9.2: Fachvortrag

Dienstag, 23. März 1999, 10:15–10:45, Phy

Ring formation in evaporating porphyrin derivative solutions — •Ralf Blossey¹, L. Latterini², J. Hofkens², P. Vanoppen², F.C. De Schryver², A.E. Rowan³, and R.J.M. Nolte³ — ¹Labo VSM, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium — ²Department of Chemistry, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium — ³Department of Organic Chemistry, NSR Center, University of Nijmegen, Toernooiveld, NL-6525 ED Nijmegen, The Netherlands

A study of the formation of micrometer-sized ring shaped

structures in evaporating solutions of porphyrin based molecules

on glass is reported. Solute concentration, solution and

substrate temperature, vapor pressure, and solvent are varied.

After solute deposition the substrates are monitored by

confocal fluorescence microscopy (CFM), atomic force

microscopy (AFM) and near-field scanning optical microscopy

(NSOM). The experimental results, supported by a model

calculation, provide evidence that the structure formation

process in the liquid film is caused by the evaporation process,

which drives both a film instability and the solute enrichment

at the rims of the droplets that appear after film rupture.