Dresden 2003 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

DS: Dünne Schichten

DS 12: Schichtwachstum II

DS 12.3: Vortrag

Mittwoch, 26. März 2003, 15:45–16:00, GER/37

Two-dimensional transport and multilayer formation: Triacontane at planar solid/air interfaces — •Paul Lazar, Hauke Schollmeyer, and Hans Riegler — Max Planck Institute of Colloids and Interfaces, Am Muehlenberg 1, 14476 Golm

The thermodynamically most stable solid bulk phase of the n-alkane triacontane at smooth, planar SiO2/air interfaces is a multilamellar film with the lamellae parallel and the molecular axis normal to the interface /1-3/. Under No-dqnormalNo-dq solidification conditions (slow sample cooling) this lowest energy configuration is not obtained: the liquid alkane droplets solidify into more or less amorphous bulk. However if the system is carefully undercooled, it occurs quite often that solid multilayer discs of uniform thickness grow radially from a central, liquid bulk droplet. The observed growth is quantitatively explained by a model which assumes that the droplet perimeter serves as alkane source, the radially growing multilayer perimeter is an alkane sink, and the alkane molecules flow (diffuse) continuously outward on top of the solid multilayer disk. It can be assumed that this scenario is quite representative for many similar systems (e.g. thin films of polymers or LCs).

1.) C. Merkl, T. Pfohl, and H. Riegler, Phys. Rev. Lett. 79(2): 4625 (1997)

2.) A. Holzwarth, S. Leporatti, and H. Riegler, Europhysics Letters 52(6): 653 (2000)

3.) H. Schollmeyer, B. Ocko, and H. Riegler, Langmuir 18: 4351