  We present a non-reactive force field for molecular dynamics simulations of
interfaces between passivated amorphous surfaces and their interaction with
water. The force field enables large-scale dynamic simulations of dry and
lubricated tribological contacts and is tailored to surfaces with hydrogen,
hydroxyl and aromatic surface passivation. To favour its compatibility with
existing force-field parameterizations for liquids and allow a straightforward
extension to other types of surface passivation species, we adopt the commonly
used OPLS functional form. The optimisation of the force-field parameters is
systematic and follows a protocol that can be reused for other surface-molecule
combinations. Reference data are calculated with gradient- and
dispersion-corrected density functional theory and include the bonding
structure and elastic deformation of bulk and surface structures as well as
surface adhesion and water adsorption energy landscapes. The conventions
adopted to define the different force-field atom types are based on the
hybridisation of carbon orbitals and enable a simple and efficient parameter
optimisation strategy based on quantum-mechanical calculations performed only
on crystalline reference structures. Transferability tests on amorphous
interfaces demonstrate the effectiveness of this approach. After testing the
force field, we present two examples of application to tribological problems.
Namely, we investigate relationships between dry friction and the corrugation
of the contact potential energy surface and the dependency of friction on the
thickness of interface water films. We finally discuss the limitations of the
force field and propose strategies for its improvement and extension.
