Berlin 2005 – wissenschaftliches Programm

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O: Oberflächenphysik

O 27: Phasenüberg
änge

O 27.7: Vortrag

Samstag, 5. März 2005, 16:30–16:45, TU EB107

Submonolayer coverage of long chain alkanes at SiO2/air interfaces: Nucleation, molecular mobility, and structure formation — •Ralf Köhler and Hans Riegler — MPI für Kolloid- und Grenzflächenforschung, Abt. Grenzflächen, 14424 Potsdam

The ordering behavior of submonolayers of long chain alkanes at SiO2/air interfaces is astonishing complex. Two-dimensional nucleation and structure formation occurs below the surface melting point. The observed fractal crystallites (1,2) can be related to a process analogous to diffusion-limited aggregation (3). One observes different growth scenarios depending on the initial thickness of the liquid alkane film, i.e., due to different supply conditions to the growth front. The system also shows a reversible (equilibrium)-coexistence of solid domains and remaining fluid film in between. On-line optical microscopy observations on recent results are presented and analyzed. (1) A.Holzwarth et al., Europhys.Lett.2000,52,653 (2) H.Schollmeyer et al., Langmuir 2003,19,5042 (3) L.Knüfing et al., Langmuir, in press