The key role of stick-slip in friction and wear processes on the nanoscale

Enrico Gnecco / Friedrich Schiller University Jena

February 24, 2021, 2 - 3 pm CET

Online live talk

Introduction

Atomic force microscopy (AFM) is one of the most efficient tools for investigating sliding friction and related phenomena down to the molecular scale. Here, a sharp probe can be used to manipulate nanostructures already existing on a surface or to forge new ones by repeatedly scraping the surface itself. In this talk, I will first present results on polyfluorene chains, graphene nanoribbons and single-stranded DNA manipulated on metal surfaces in an ongoing collaboration with the University of Basel, and on metal clusters forming contacts with various degrees of commensurability recently studied by my group. If the surface itself is “manipulated” by the AFM tip, it becomes possible to observe and quantify early stages of abrasive wear on the nanoscale, which is of utmost importance for assessing the quality of technical surfaces and possible environmental issues. Particularly instructive in this content are the cases of compliant polymers and layered materials, where ripples, round-shaped nanoparticles, and flakes are easily generated out of the nanoscratch processes. The common denominator of the processes presented in the talk is the stick-slip mechanism determining the evolution of the friction forces in the sliding contacts. It will be also discussed in its simplicity and beauty based on a model originally developed by Ludwig Prandtl and extended in various ways to describe most of the previous experimental situations.

Enrico Gnecco

Enrico Gnecco is Professor of Mechanics of Functional Materials at Friedrich Schiller University Jena since 2015. His current research activity focuses on sliding friction in different environmental conditions, scanning probe microscopy-based manipulation, contact mechanics and abrasive wear processes on the nanoscale. Prof. Gnecco authored several articles on nanotribology in major journals including Science, Nature Materials, PNAS and Nano Letters and two books. In his spare time he used to play the piano and write short pieces of music.

Enrico Gnecco edited the thematic issue "Nanotribology" together with Susan Perkin, Andrea Vanossi and Ernst Meyer in the Beilstein Journal of Nanotechnology. Download the complete PDF of this issue with one click!

Contact

The Beilstein Talks are organized by the Beilstein-Institut.
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