title: Water tribology on graphene.
abstract: Classical experiments show that the force required to slide liquid drops on surfaces increases with the resting time of the drop, t(rest), and reaches a plateau typically after several minutes. Here we use the centrifugal adhesion balance to show that the lateral force required to slide a water drop on a graphene surface is practically invariant with t(rest). In addition, the drop's three-phase contact line adopts a peculiar micrometric serrated form. These observations agree well with current theories that relate the time effect to deformation and molecular re-orientation of the substrate surface. Such molecular re-orientation is non-existent on graphene, which is chemically homogenous. Hence, graphene appears to provide a unique tribological surface test bed for a variety of liquid drop-surface interactions.
authors.affiliation: Dan F. Smith Department of Chemical Engineering, Lamar University, P. O. Box 10053, Beaumont, Texas 77710, USA.
authors.forename: Hartmann E
authors.initials: HE
authors.lastname: N'guessan
authors.forename: Aisha
authors.initials: A
authors.lastname: Leh
authors.forename: Paris
authors.initials: P
authors.lastname: Cox
authors.forename: Prashant
authors.initials: P
authors.lastname: Bahadur
authors.forename: Rafael
authors.initials: R
authors.lastname: Tadmor
authors.forename: Prabir
authors.initials: P
authors.lastname: Patra
authors.forename: Robert
authors.initials: R
authors.lastname: Vajtai
authors.forename: Pulickel M
authors.initials: PM
authors.lastname: Ajayan
authors.forename: Priyanka
authors.initials: P
authors.lastname: Wasnik