ILs on Solid-State Surfaces

The physics of ILs at surfaces are important for a deeper understanding of the resulting properties and enables the design of appHcations. Each combination of cation and anion can lead to a different behavior on surfaces of sohds, because the molecular structure of each IL has a strong influence of the formation of layers at the interfaces. In aqueous electrolytes the Hehnholtz-model and its further developments are describing the physics in a sufficient way The Gouy-Chapman-model takes the diffusion into account, and the Stem-model combines the formation of a double layer with diffusion. Compared to aqueous solutions of salts, the situation in ILs is different The ions have no solvent environment Their next neighbors are also ions. As a consequence the physics at the interfaces between sohds and ILs cannot be described by the common models. 

This underlines the need of ILs being as pure as possible. Furthermore, because no substance is 100% pure, it is necessary to quantify impurities accurately, for example, for inorganic impurities by ion chromatography. 

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