AVS 46th International Symposium
    Nanometer-scale Science and Technology Division Tuesday Sessions
       Session NS1-TuM

Invited Paper NS1-TuM3
Contact Properties of Oxide Surfaces: Long Range Forces and Adhesion

Tuesday, October 26, 1999, 9:00 am, Room 612

Session: Nanomechanics
Presenter: E. Barthel, CNRS / Saint Gobain Recherche, France
Authors: E. Barthel, CNRS / Saint Gobain Recherche, France
A.S. Huguet, CNRS / Saint Gobain Recherche, France
R. Roquigny, CNRS / Saint Gobain Recherche, France
S. Sounilhac, CNRS / Saint Gobain Recherche, France
Correspondent: Click to Email
Surface Forces Microscopy (SFM) is useful to caracterize adhesive properties of surfaces. In practice, however, the usual relations between pull-off force and adhesion energy (JKR, DMT) may sometimes be inadequate, because the assumptions inherent to these models are not fulfilled. Using a general approach to the adhesive contact problem, based on Sneddon's results, and specific descriptions of the interaction(s) relevant to the cases under study, we will consider three non-trivial cases: 1) Silica/silica contact: in this case, both very short-range and long-range interactions contribute. We show how to split the total adhesion energy into its long-range and short-range contributions.@footnote 1@ 2) Surfactant monolayers: recent experiments@footnote 2@ have evidenced a power law dependance of the pull-off force as a function of driving velocity when surfactant monolayers are deposited on the surfaces. We provide an analytical model for this case, where viscoelastic losses are essential 3) Metal/oxide contact: using an UHV AFM, we have investigated the tungsten/oxide adhesion and long range forces.@footnote 3@ Short-range forces are shown to form the main contribution, although we did not achieve quantitative assesment. CONCLUSION Surface Forces measurements are a versatile tool for understanding interaction and adhesion properties of oxide surfaces. However, the bare pull-off force may reflect a variety of phenomena, which have to be properly taken into account in the data treatment. @FootnoteText@ @footnote 1@ Barthel E., Colloids and Surfaces A, 1999, 149, 99. @footnote 2@ Ruth M. and Granick S., Langmuir, 1998, 14, 1804. @footnote 3@ Sounilhac S., Barthel E. and Creuzet F., J. Appl. Phys., 1999, 85, 222.