Intermittent contact scanning force microscopy: The role of the liquid necks

Publisher Website
Google Scholar
Abstract
We have studied the intermittent contact mode for small oscillation amplitudes and soft cantilevers with sharp tips. For appropriate working conditions the tip does not touch the mica surface. Instead, a high dissipative tip–sample interaction takes place which reduces the oscillation amplitude of the cantilever. Our experiments show that this dissipative interaction is related to the relative humidity and we believe that it is induced by a nanometer sized liquid neck between tip and sample. A phase contrast image on different surface materials is then due mainly to the wetting properties of the corresponding material rather than to their elastic or viscoelastic properties. The intermittent contact mode described in this work is especially advantageous since the tip is extremely gentle with the surface.