Towards an understanding of friction at electrodes on the atomic scale

• Applicant: Professor Dr. Helmut Baltruschat
• Subject Area: Physical Chemistry of Molecules, Liquids and Interfaces, Biophysical Chemistry ; Physical Chemistry of Solids and Surfaces, Material Characterisation
• Term: from 2016 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 288879147

• Final Report Year: 2025

Final Report Abstract

Friction is one of the most important origins of energetic losses. In this project we studied atomic scale friction using lateral force microscopy for various systems (copper, silver and iodine monolayers as well as a lipid bilayer, both in aqueous and aprotic electrolytes) as function of potential on a Au(111) single crystal surface. We routinely obtained atomic resolution; for low normal loads we reproduced structures reported before obtained e.g. by STM. For higher normal loads, structures often changed to that of the metallic under-layer indicating a penetration of the tip at least through the outermost layer. In general, friction (or the friction coefficient) is low at high potentials where no metallic layer is adsorbed, or at very low potentials where the metallic adlayer is so strongly adsorbed that the layer cannot be penetrated by the tip. Penetration of the tip through a layer leads to a large increase in friction, demonstrating that the frictional energy dissipation under those conditions is mainly due the displacement/desorption of the adsorbate during the tip scan. Steps in force separation curves clearly indicated displacement of solvent and dissolved ions from the surface or compression of the lipid layer. Displacement of the strongly adsorbed atoms was not possible under static conditions without scanning, obviously a shear force is necessary.

Publications

• Friction at electrode surface in aprotic electrolytes: Effect of adsorbates and potential, International Nanotribology Forum, 13.01.2020 ~ 17.01.2020, ChiangRai, Thailand.
  I. Park & H. Baltruschat
  
• Friction at electrode surface: Effect of adsorbates and potential, 71st Annual Meeting of the International Society of Electrochemistry, 31.08.2020 ~ 01.09.2020, virtual meeting.
  I. Park & H. Baltruschat
  
• Atomic-scale friction study: Underpotential deposition (UPD) of silver on I-modified Au(111) in aprotic electrolyte, 116th AGEF symposium: Triboelectrochemistry, 22.09.2021~ 24.09.2021, Bonn, Germany.
  I. Park & H. Baltruschat
  
• Atomic-scale friction study: Underpotential deposition (UPD) of silver on I-modified Au(111) in aprotic electrolyte, Friction 2021, 18.11.2021~19.11.2021, virtual meeting.
  I. Park & H. Baltruschat
  
• In situ friction study of Ag Underpotential deposition (UPD) on Au(111) in aqueous electrolyte. ChemPhysChem, 22(10), 952-959.
  Park, Inhee & Baltruschat, H.
  
• Sulfate adsorption on Au(111) electrodes – Influence of the potential on the force distance curves, 116th AGEF symposium: Triboelectrochemistry, 22.09.2021~ 24.09.2021, Bonn, Germany
  Andreas Köllisch & H. Baltruschat
  
• Atomic-Scale Friction Study by EC-AFM: Underpotential Deposition (UPD) of Ag on I-Modified Au(111) and Its Tip Penetration. Journal of The Electrochemical Society, 169(12), 122501.
  Park, Inhee & Baltruschat, H.
  
• Atomic-Scale Friction Study: Underpotential Deposition (UPD) of Silver on I-Modified Au(111) in Aprotic Electrolyte (E02-1179), 241st ECS Meeting | 29.05 – 02.06. 2022, Vancouver, BC, Canada
  I. Park & H. Baltruschat
  
• Atomic-scale friction study: Underpotential deposition (UPD) of silver on I-modified Au(111) in aqueous and aprotic electrolytes, Gordon Research Conference Tribology (GRS), 25.06.2022~26.06.2022, Lewiston, USA.
  I. Park & H. Baltruschat
  
• Atomic-scale friction study: Underpotential deposition (UPD) of silver on I-modified Au(111) in aqueous and aprotic electrolytes, Gordon Research Conference Tribology, 26.06.2022~01.07.2022, Lewiston, USA.
  I. Park & H. Baltruschat
  
• Friction on I‐Modified Au(111) in a Tetraglyme Electrolyte. ChemElectroChem, 9(9).
  Park, Inhee; Hausen, Florian & Baltruschat, Helmut
  
• Atomic-Scale Tribology: Influencing Friction by Electrode Potential and Monolayers, 74th Annual Meeting of the International Society of Electrochemistry, 03.09. – 08.09.2023, Lyon, France,
  Helmut Baltruschat, Inhee Park & Andreas Koellisch-Mirbach
  
• 1 The Electrochemistry of Sodiumdodecylsulfonate on Au(111) in sulfuric acid – Voltammetry, Adsorbate structure and Friction. American Chemical Society (ACS).
  Koellisch‐Mirbach, Andreas; Park, Inhee & Baltruschat, Helmut
  
• The Effect of Monolayers on Atomic-scale Friction in Aprotic Electrolytes: Underpotential Deposition (UPD) of Silver on I-modified Au(111). American Chemical Society (ACS).
  Park, Inhee; Hausen, Florian & Baltruschat, Helmut