Dresden 2003 – wissenschaftliches Programm

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O: Oberflächenphysik

O 24: Postersitzung (Epitaxie und Wachstum, Oxide und Isolatoren, Elektronische Struktur, Oberfl
ächenreaktionen, Adsorption an Oberfl
ächen, Organische Dünnschichten)

O 24.72: Poster

Mittwoch, 26. März 2003, 14:30–17:30, P1

An AFM investigation of the growth of an octadecylsiloxane monolayer: The adsorption of reversed micelles — •Nils Hartmann, Rafael Bautista, Daniel Dahlhaus, Steffen Franzka, and Eckart Hasselbrink — Universität Essen, Fachbereich Chemie, Universitätsstr. 5, 45141 Essen

Ex situ atomic force microscopy (AFM) was used to study the growth of an octadecylsiloxane monolayer during immersion of oxidized silicon substrates in millimolar solutions of octadecyltrichlorosilane (OTS) in toluene with a comparatively high water content. AFM images of the coated substrates display several circular features with a lateral diameter between 20 and 200 nm and varying heights. The general appearance of these features reminds of partially deflated ballons. In accordance with a previous investigation focusing on the growth of a fluorinated alkylsiloxane monolayer [1], we attribute these features to reversed micelles that are formed in solution prior to adsorption. In some instances the micelles appear to act as nuclei for the subsequent growth of the octadecylsiloxane islands. A mechanism including the initial adsorption of reversed micelles and their subsequent partial rearrangement on the surface is discussed.

[1] B. C. Bunker, R. W. Carpick, R. A. Assink, M. L. Thomas, M. G. Hankins, J. A. Voigt, D. Sipola, M. P. de Boer and G. L. Gulley, Langmuir 16 (2000) 7742.