  Hydrocarbon tribopolymer, a type of polymer formed due to friction between
surfaces, is a major impediment to the development of micro- and
nanoelectromechanical systems (MEMS/NEMS) devices for industrial application.
Tribopolymer buildup can prevent MEMS and NEMS from making or breaking
electrical contact. We describe the adsorption of benzene (C6H6) on the
RuO2(110) surface using density functional theory. This adsorption is an
important initial step in the mechanism of hydrocarbon tribopolymer layer
formation on MEMS and NEMS devices. The adsorption interaction is studied by
considering three oxygen coverages of RuO2(110) and all the possible adsorption
sites for benzene. We find that adsorption of benzene on O-poor RuO2(110) via
C-Ru bonds is stronger than adsorption on the O-rich RuO2(110) via H-O bonds.
For an in-depth study of the adsorption behavior, we include the van der Waals
interaction for a holistic investigation. By incorporating the thermodynamic
chemical potentials into the adsorption simulations, we describe a model that
can provide guidance for realistic situations.
