title: Nanoscale lubrication of ionic surfaces controlled via a strong electric field.
abstract: Frictional forces arise whenever objects around us are set in motion. Controlling them in a rational manner means gaining leverage over mechanical energy losses and wear. This paper presents a way of manipulating nanoscale friction by means of in situ lubrication and interfacial electrochemistry. Water lubricant is directionally condensed from the vapor phase at a moving metal-ionic crystal interface by a strong confined electric field, thereby allowing friction to be tuned up or down via an applied bias. The electric potential polarity and ionic solid solubility are shown to strongly influence friction between the atomic force microscope (AFM) tip and salt surface. An increase in friction is associated with the AFM tip digging into the surface, whereas reducing friction does not influence its topography. No current flows during friction variation, which excludes Joule heating and associated electrical energy losses. The demonstrated novel effect can be of significant technological importance for controlling friction in nano- and micro-electromechanical systems.
authors.affiliation: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831.
authors.forename: Evgheni
authors.initials: E
authors.lastname: Strelcov
authors.affiliation: 1] Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831 [2] Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831.
authors.forename: Rajeev
authors.initials: R
authors.lastname: Kumar
authors.affiliation: Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831.
authors.forename: Vera
authors.initials: V
authors.lastname: Bocharova
authors.affiliation: 1] Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831 [2] Computer Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831.
authors.forename: Bobby G
authors.initials: BG
authors.lastname: Sumpter
authors.affiliation: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831.
authors.forename: Alexander
authors.initials: A
authors.lastname: Tselev
authors.affiliation: Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN 37831.
authors.forename: Sergei V
authors.initials: SV
authors.lastname: Kalinin