Contact Angle Analysis during the Electro-Oxidation of N-Octadecyltrichlorosilane Monolayers
-
Herzer, Nicole; van Schaik, Jurriaan H. K.; Höppener, Stephanie; Schubert, Ulrich S.
- Abstract:
- The electrochemical oxidation process of self-assembled monolayers formed
by n -octadecyltrichlorosilane (OTS) molecules on silicon wafers has been
studied in a droplet of water by means of in situ water contact angle measurements.
The application of different bias voltages between the substrate and a
counter electrode placed into the droplet resulted in changes of the chemical
nature of the monolayer, which yielded a signifi cant alteration of the surfaces
properties. Due to the changes of the wetting properties of the monolayer
during the electro-oxidation process a change in the contact angles of the
water droplet is concomitantly observed. This allows the in situ monitoring of
the electro-oxidation process for large modifi ed areas of several millimeters
in diameter. The chosen approach represents an easy way to screen the major
parameters that infl uence the oxidation process. Afterwards, the oxidized
regions are characterized by Fourier-transform infrared (FT-IR) spectroscopy,
X-ray photoelectron spectroscopy (XPS) measurements, and atomic force
microscopy (AFM) investigations to obtain more information about the
electro-oxidation process. The observations are correlated to experimental
results obtained for oxidations performed on a smaller dimension range in
the water meniscus of a conductive, biased AFM tip. A good correlation of the
results in the different dimension ranges could be found.
- Year:
- 2010
- Type of Publication:
- Article
- Journal:
- Advanced Functional Materials
- Volume:
- 20
- Pages:
- 3252 - 3259