IUVSTA 15th International Vacuum Congress (IVC-15), AVS 48th International Symposium (AVS-48), 11th International Conference on Solid Surfaces (ICSS-11)
    Surface Science Tuesday Sessions
       Session SS+BI-TuA

Paper SS+BI-TuA7
Study of Alkylsilane Monolayers Islands on Mica in the Presence of Water

Tuesday, October 30, 2001, 4:00 pm, Room 120

Session: Poirier Memorial Session: Self-Assembled Monolayers II
Presenter: M. Luna, Lawrence Berkeley National Laboratory
Authors: M. Luna, Lawrence Berkeley National Laboratory
I. Diez, Universitat de Barcelona, Spain
F. Teran, Universitat de Barcelona, Spain
F. Sanz, Universitat de Barcelona, Spain
D.F. Ogletree, Lawrence Berkeley National Laboratory
M. Salmeron, Lawrence Berkeley National Laboratory
Correspondent: Click to Email
The increasing interest in the study of self-assembled monolayers for the last two decades is related to their potential in different fields of science and technology such as biological sensors, @footnote 1@ optoelectronics,@footnote 2@ tribology@footnote 3@ and corrosion inhibition. @footnote 4@ The knowledge of the stability of the packing, the electrostatic and dielectric properties, and the understanding of the formation process of SAMs constitute crucial phenomena to be investigated in the presence of a changing relative humidity atmosphere. Thus we have performed several series of experiments on alkylsilane monolayer islands vs. relative humidity by means of Polarization Force Microscopy and Dynamic Force Microscopy. The results show that the autoorganizacion is achieved starting from a layer where the molecules are lying down. Also, due to the hydrophilic properties of the alkylsilane monolayer islands, water adsorbs only on mica. This produces an important increase of the dielectric constant on the mica which, in polarization force microscopy, reverses the topographic contrast at around 30% and reaches a maximum at 80%. In addition, by measuring the relative topographic distance between the mica and the islands we are able to quantify the amount of water adsorbed on mica at high relative humidity. . @FootnoteText@ @footnote 1@ K. Shierbaum, T. Weiss, E. T. van Velzen, J. Engbersen, D. Reinhoudt and W. Göpel, Science 265, 1413 (1994). @footnote 2@ A. Ulman, Thin Films: Self-Assembled Monolayers of Thiols, Academic Press, New York, 1998. @footnote 3@ J. I. Siepmann and I. R. McDonald, Phys. Rev. Lett. 70, 453 (1993). @foornote 4@ F. Zamborini and R. Crooks, Langmuir 14, 3279 (1998).