Abstract
The friction and adhesion between a fluorocarbon monolayer-coated surface against a hydrocarbon monolayer-coated surface has been directly measured. The friction was found to be lower than the friction between a hydrocarbon monolayer against a hydrocarbon monolayer and a fluorocarbon monolayer against a fluorocarbon monolayer. No stick-slip sliding was observed for speeds from 0.8 µm/s to 2.6 µm/s. The fluorocarbon–hydrocarbon interface was adhesive, with the energy of interaction measured to be 14.9 mJ/m2 ± 1.0 mJ/m2. As predicted from theory, the magnitude of the adhesion of a fluorocarbon monolayer against a hydrocarbon monolayer is between that measured for a fluorocarbon monolayer against a fluorocarbon monolayer and a hydrocarbon monolayer against a hydrocarbon monolayer. One may note that the interfacial energy, γ, follows the general trend γFC/FC < γHC/FC < γHC/HC, whereas the shear stress, τ, varies according to τFC/HC < τHC/HC < τFC/FC.
Acknowledgments
One of a collection of papers honoring Jacob Israelachvili, the recipient in February 2003 of The Adhesion Society Award for Excellence in Adhesion Science, Sponsored by 3M.
Presented in part at the 26th Annual Meeting of The Adhesion Society, Inc., Myrtle Beach, South Carolina, USA, 23–26 February 2003.
Certain commercial equipment, instruments, or materials are identified in this article in order to adequately specify the experimental procedure. Such identification does not imply recommendation or endorsement by the National Institute of Standards and Technology nor does it imply that the materials or equipment are necessarily the best available for the purpose.