Regensburg 2019 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 67: Polymer and Molecular Dynamics, Friction and Rheology

CPP 67.9: Vortrag

Freitag, 5. April 2019, 12:00–12:15, H13

Influence of interface hydration on sliding of graphene and molybdenum disulfide single-layers — •Hu Lin, Abdul Rauf, Nikolai Severin, Igor M. Sokolov, and Jürgen P. Rabe — Department of Physics & IRIS Adlershof, Humboldt-Universität zu Berlin, Germany

Humidity influences friction in layered materials in peculiar ways. For example, while water improves the lubricating properties of graphite, it deteriorates those of molybdenum disulfide (MoS2). The reasons remain debated, not the least due to the difficulty to experimentally compare dry and hydrated interface frictions. For this, we strain the mica substrate and detect strain in graphene and MoS2 by changes in Raman and photoluminescence spectra, respectively. The spectra show that the hydration of interfaces between a mica substrate and single-layers of graphene and MoS2 with a molecularly thin water layer affects strain transfer from the substrate to the 2D materials. Strain relaxation in graphene changes from stick-slip in dry contact, to viscous when hydrated. In contrast, there is no viscous relaxation in MoS2 regardless of hydration. Our work provides a novel approach for better understanding the impact of hydration on friction in layered materials.