Regensburg 2019 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 23: Solid-Liquid Interfaces II: Electrode Surfaces

O 23.7: Vortrag

Dienstag, 2. April 2019, 12:15–12:30, H5

Investigation of ion mobility and material transport on KBr surfaces in air in dependence of the relative humidity. — •Dominik Kirpal, Korbinian Pürckhauer und Franz Giessibl — University of Regensburg, Regensburg, Germany

On every surface exposed to humid air a thin film of water molecules forms. The presence of water plays an important role for chemical reactions, material exchange and movement. The effect of condensed water layer, present in ambient conditions plays a significant role especially on surfaces that dissolve easily in water [1]. Surface atoms can easily diffuse into the thin water layer and, when surface conditions are favourable, they can re-attach to the surface. We collected FM-AFM images of the KBr surface in a climate-controlled glove box at various values of relative humidity. By scratching the surface with the AFM tip, we construct energetically unfavourable hills and scratch sites. We observe the time evolution of these sites. We propose that there is a critical value around 25% relative humidity, under which dissolution and reattachment occurs relatively slowly, in contrast to our observations at 28% relative humidity where these processes occur quickly.

[1] M. Luna, et al., Journal of Physical Chemistry A, 102.34 (1998) 6793-6800.