Dresden 2020 – wissenschaftliches Programm
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CPP 60.2: Vortrag
Mittwoch, 18. März 2020, 11:45–12:00, ZEU 222
Screening lengths in ionic fluids — Fabian Coupette1, Alpha A. Lee2, and •Andreas Härtel1 — 1Institut of Physics, University of Freiburg, Germany — 2Cavendish Laboratory, Cambridge, United Kingdom
The decay of correlations in ionic fluids is a classical problem in soft matter physics that underpins applications ranging from controlling colloidal self-assembly to batteries and supercapacitors. The conventional wisdom, based on analyzing a solvent-free electrolyte model, suggests that all correlation functions between species decay with a common decay length in the asymptotic far field limit. Nonetheless, a solvent is present in many electrolyte systems. We show using an analytical theory and molecular dynamics simulations that multiple decay lengths can coexist in the asymptotic limit as well as at intermediate distances once a hard sphere solvent is considered. Our analysis provides an explanation for the recently observed discontinuous change in the structural force across a thin film of ionic liquid-solvent mixtures as the composition is varied, as well as reframes recent debates in the literature about the screening length in concentrated electrolytes.