title: Molecular dynamics study of alkylsilane monolayers on realistic amorphous silica surfaces.
abstract: Interfacial properties of n-alkylsilane monolayers on silica have been investigated with molecular dynamics simulations using both reactive and classical (i.e., nonreactive) force fields. A synthesis mimetic simulation (SMS) procedure using the reactive force field ReaxFF has been developed to mimic the experimental processing of silicon wafers involved in the preparation of alkylsilane monolayers; in the SMS procedure, amorphous silica surfaces are generated and exposed to hydrogen peroxide (H2O2) to create a hydroxide surface layer. Alkylsilane monolayers are then assembled on these surfaces, and their behavior is studied. To investigate the impact of the SMS procedure on monolayer properties, simulations have also been performed using more idealized monolayers assembled on crystalline surfaces and non-H2O2-processed amorphous surfaces. The simulations reported here demonstrate that processing-induced silica surface roughness plays a key role in the structure and frictional performance of monolayers. Furthermore, ignoring these effects results in a significant underestimation of the coefficient of friction and an overestimation of the orientational ordering of the monolayers.
authors.affiliation: †Department of Chemical and Biomolecular Engineering, ‡Multiscale Modeling and Simulation (MuMS), and §Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States.
authors.forename: Jana E
authors.initials: JE
authors.lastname: Black
authors.affiliation: †Department of Chemical and Biomolecular Engineering, ‡Multiscale Modeling and Simulation (MuMS), and §Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Iacovella
authors.affiliation: †Department of Chemical and Biomolecular Engineering, ‡Multiscale Modeling and Simulation (MuMS), and §Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States.
authors.forename: Peter T
authors.initials: PT
authors.lastname: Cummings
authors.affiliation: †Department of Chemical and Biomolecular Engineering, ‡Multiscale Modeling and Simulation (MuMS), and §Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37235, United States.
authors.forename: Clare
authors.initials: C
authors.lastname: McCabe