INVESTIGATION OF SURFACE CHANGES ON MICA INDUCED BY ATOMIC-FORCE MICROSCOPY IMAGING UNDER LIQUIDS

Surface changes oil muscovite mica induced by tip-surface interactions in atomic Force microscopy (AFM) experiments under liquids are descri bed. investigations have been performed with AFM operated both in cont act mode (CM-AFM) and in tapping mode (TM-AFM). Additionally, force-di stance measurements have been carried out. In contrast to CM-AFM prono unced surface changes can be observed in TM-AFM experiments. However. TM-AFM images of areas previously scanned in contact mode show that im aging contact made changes the surface, too. An evaluation of force-di stance measurements reveals that these changes depend on the adhesive interaction between tip and sample, which in turn strongly depends on the surrounding medium. The artefact can be avoided by changing the pH -value of the medium or by working with mixtures of ethanol and water. This greatly enhances the applicability of TM-AFM for in-situ investi gation of surface processes on mice, which is a frequently used substr ate for many technological and biological applications.