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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 57: Complex Fluids and Colloids, Micelles and Vesicles II (joint session CPP/DY)

CPP 57.2: Vortrag

Freitag, 31. März 2023, 10:00–10:15, MER 02

Structure/Friction relationship in solid supported phospholipid layers — •Swen Helstroffer, Pierre Muller, and Thierry Charitat — Institute Charles Sadron, Strasbourg, France

Stacks of phospholipid bilayers adsorbed on biological rubbing surfaces lubricate remarkably well under severe conditions. However, the energy dissipation pathway allowing ultra low friction is still unknown. To elucidate the mechanism, we propose here to study an experimental model consisting of hydrated phospholipid layers deposited at the air/solid interface. Our system presents a well-controlled geometry in which we can fine-tune the hydration level of the lipid heads. By combining neutron reflectometry and ellipsometry studies with macroscopic tribology experiments, we demonstrated a negative correlation between hydration and friction coefficient. Using the Eyring model, we obtained microscopic activation volumes characteristic of slip. Our results suggest that the hydration level is a key parameter for lubrication. We believe that the sliding plane is located in the confined water layers.