Berlin 2018 – scientific programme

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O: Fachverband Oberflächenphysik

O 45: Poster: Solid-Liquid Interfaces - Structure, Spectroscopy, Reactions and Electrochemistry

O 45.1: Poster

Tuesday, March 13, 2018, 18:15–20:30, Poster A

Observation of material movement on KBr surfaces depending on the relative humidity — •Dominik Kirpal, Korbinan Pürckhauer, Alfred J. Waymouth, and Franz J. Giessibl — University of Regensburg, Regensburg, Germany

Surfaces exposed to air can change their structure due to external influences like chemical reactions or material exchange and movement. The condensed water layer, present in ambient conditions plays an important 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.