Working group 2

The aim here is to develop the fundamental nanoscale design enabling friction control, by causing the tribological properties to vary at will under some external action. Focus will be on exploiting novel methods and solutions, since standard (macroscopic) manipulation and lubrication techniques are much less effective or impractical in the micro- and nano-world.

Main objectives

  • Control nanofriction by the application of mechanical, electrochemical, and electrostatic actuation.
  • Investigate the robustness of superlubric effects and ultra-low friction operative conditions against a variety of energy dissipation mechanisms, e.g., dislocation formation, plastic deformation, wear…
  • Address the effects of electronic vs. phononic friction.
  • Probe superlubricity of liquids at solid surfaces.
  • Understand the influence of surface treatments on nanoscale friction and wear.
  • Exploit surface pattern geometries to control/suppress highly dissipative regimes of motion.
  • Exploit the effect of phase transitions, either in the sliders or in the intervening lubricant, on sliding fiction.

Methods A

Experimental: *FFM (ambient, liquids and ultrahigh vacuum) in combination with mechanical and electrostatic actuation, and with a variety of probing tips, different geometry, sample structures and patterns. *Standard and pendulum-type AFM to investigate dissipation across phase transitions like the metal-superconductor transition. *Design of a hierarchical macro to nanofluidic experimental device with a single carbon nanotube as nanofluidic system.

Methods B

Theoretical: *Molecular dynamics (MD) simulations methods to analyse the detail of the internal rates of surface structural rearrangement during sliding. *Implementation of reliable single- and multi-contact models to correlate the tribological behaviour recorded in experiments and the dynamics of microscopic events at the sliding interface. *Search for simpler models capturing the general features of the multifaceted tribological processes observed in experiments or realistic MD simulations. *Development of new approaches to control nanofriction on substrates whose properties are affected by electronic quantum-mechanical transitions, e.g. magnetic and superconducting ones.