Dresden 2009 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 39: POSTERS Colloids and Liquids

CPP 39.30: Poster

Donnerstag, 26. März 2009, 17:00–19:30, P3

Stability of free flying liquid films — •Pascal Frank, Johannes Boneberg, and Paul Leiderer — Universität Konstanz, Deutschland

A 10 ns laser pulse is used to rapidly heat the surface of a silicon substrate, where a thin (100-500nm) liquid film is deposited on top. The subsequent phase transition of the first ten nanometers at the interface leads to desorption and acceleration of this film. Ns-time resolved reflectometry allows to determine the actual position of the free flying liquid film. The measurements show that under ambient conditions the flight is parabolic and the film returns to the substrate after some hundred nanoseconds as the accelerating pressure rapidly decreases below the ambient pressure with increasing distance to the substrate. The maximal distance of the film is up to a few micrometers. The liquid remains stable during the time of flight of several hundred nanoseconds. If the exciting laser pulse is modulated via laser interference with periods exceeding thermal conduction length during the pulse, the film thickness can be modulated as well. Investigation of the diffraction provides insights to the stability of this modulation and the whole film.