Measuring the Friction of Nanoparticles: A New Route towards a Better Understanding of Nanoscale Friction

Abstract

Tribology--the science of friction, wear, and lubrication--is of considerable importance for all technical applications where moving bodies are in contact. Nonetheless, little progress has been made in finding an exact atomistic description of friction since Amontons proposed his empirical macroscopic laws over three centuries ago. The advent of new experimental tools, such as the friction force microscope, however, has enabled the investigation of frictional forces down to the atomic scale. Recently, this tool has been used to measure the friction of nanoparticles sliding over flat surfaces, thereby enabling a much larger range of material combinations and interface contact areas to be studied. These advances offer new insight into the atomistic concepts of friction.

Quantifying Pathways and Friction of Nanoparticles During Controlled Manipulation by Contact-Mode Atomic Force Microscopy

“…Over the last few years, however, a growing number of experimental and theoretical studies have looked into how nanoparticle manipulation can be used as a tool for nanotribology [16][17][18][19][20][21][22]. By either measuring the interfacial friction during contact mode manipulation or by analyzing energy dissipation during the manipulation in dynamic AFM modes, quantitative information about nanoscale friction can be gained [23]. Among the many benefits of this particle manipulation approach to nanotribology compared to alternative methods such as conventional friction force microscopy [24] is the possibility to analyze a wide range of material combinations and to measure friction of clean, well-defined interfaces.…”

Frictional duality of metallic nanoparticles: Influence of particle morphology, orientation, and air exposure

“…Traditionally, atomic force microscopy ͑AFM͒ based manipulation of nano-objects focused on the exact positioning of particles [20][21][22][23] as well as the characterization of the factors that govern the tip-imposed particle movement. [24][25][26][27][28][29] A new route toward understanding nanoscale friction 30 has then been opened by quantifying the interfacial friction between the nanoparticle and the substrate during the manipulation process, which enables the study of the frictional behavior for a wide variety of material combinations with well-defined interface conditions. [31][32][33][34][35][36] Under ultrahigh vacuum ͑UHV͒ conditions nanoparticles can be manipulated on clean, atomically flat substrates, allowing the investigation of the atomic origins of friction for extended contacts.…”

Current trends in the physics of nanoscale friction

“…Superlubricity is experimentally rare. Until recently, it has been demonstrated or implied in a relatively small number of cases [29,[42][43][44][45][46]. There are now more evidences of superlubric behavior in cluster nanomanipulation [32,33,47], sliding colloidal layers [48][49][50], and inertially driven rare-gas adsorbates [51,52] (see Fig.…”