Visualization of Ion Distribution at the Mica-Electrolyte Interface

Local ionic environments within nanometer proximity of a surface play a major role in the interactions which occur there and can be of critical importance in, for example, colloid suspensions, as well as biological function. Such environments often vary significantly from bulk properties, as we show here by the direct imaging of a range of monovalent (Li(+), Na(+)) and divalent (Ca(2+), Mg(2+)) cations distributed at the liquid-solid interface of mica. We image local charge distributions relative to the atomic lattice of mica and adjacent structured water and explain how their location is influenced by the electrostatic characteristics of the underlying lattice.