Underscreening in concentrated electrolytes
| Autor: | Alpha A. Lee, Susan Perkin, Carla Perez-Martinez, Alexander M. Smith |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Chemical Physics (physics.chem-ph)
Activity coefficient Materials science Differential capacitance Surface force FOS: Physical sciences 02 engineering and technology Interaction energy Electrolyte Condensed Matter - Soft Condensed Matter 010402 general chemistry 021001 nanoscience & nanotechnology Bjerrum length 01 natural sciences 0104 chemical sciences Ion Condensed Matter::Soft Condensed Matter Chemical physics Physics - Chemical Physics Soft Condensed Matter (cond-mat.soft) Surface charge Physical and Theoretical Chemistry 0210 nano-technology |
| Zdroj: | Faraday Discussions |
| ISSN: | 1364-5498 |
| Popis: | Screening of a surface charge by electrolyte and the resulting interaction energy between charged objects is of fundamental importance in scenarios from bio-molecular interactions to energy storage. The conventional wisdom is that the interaction energy decays exponentially with object separation and the decay length is a decreasing function of ion concentration; the interaction is thus negligible in a concentrated electrolyte. Contrary to this conventional wisdom, we have shown by surface force measurements that the decay length is an increasing function of ion concentration and Bjerrum length for concentrated electrolytes. In this paper we report surface force measurements to test directly the scaling of the screening length with Bjerrum length. Furthermore, we identify a relationship between the concentration dependence of this screening length and empirical measurements of activity coefficient and differential capacitance. The dependence of the screening length on the ion concentration and the Bjerrum length can be explained by a simple scaling conjecture based on the physical intuition that solvent molecules, rather than ions, are charge carriers in a concentrated electrolyte. Comment: Accepted as a conference paper for "Chemical Physics of Electroactive Materials: Faraday Discussion" (10-12 April 2017, Cambridge, UK) |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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