Why Scanning Drop Friction Force Microscopy?
Are you interested in wetting phenomena? Do you suspect that you have inhomogeneous surfaces? Do you want to understand how liquids transit on surfaces? Then scanning drop friction force instrument (sDoFFI) will provide insights. sDoFFI is a novel scanning probe method enabling the characterizing of friction forces on surfaces. In sDoFFI the drop acts as the probe. Scanning of samples resolve areas with different friction forces. Differences in friction forces are related to differences in wetting properties of the sample surface. In addition to understanding of drop-surface friction forces, the sDoFFI is applicable for quality control of surfaces. The close by sDoFFI maps show tow examples of friction force measurements.
Example of a "M"-structure made by chemical vapour deposition of OTS (octyltrichlorosilane) and PFOTS (Trichloro(1H, 1H, 2H, 2H - perfluorooctyl)silane):
Example of a surface made by spray coating which are are used for coating the windshield of cars, so that rainwater does not stick to the surface, improving visibility. We used the commercially available superhydrophobic coating (Soft Glaco mirror coat zero) to prepare a sample having one half coated with three layers and the other half coated with one layer. The liquid suspension is sprayed onto the glass substrate from nearly 15-20 cm away:
How to use sDoFFI: A short video
Friction force maps can be genated within one minute. Therefore the developed sDoFFI technique for the characterization of surface wetting properties is an elegant way to overcome the temporal as well as local resolution limitations posed by standard CA goniometry. The friction force signals arising from the interaction of the three-phase contact line with the inhomogeneities are used to locate and resolve wetting features down to sub-millimeter sizes. Even surface feature having sizes much smaller than the drop diameter can be characterized. Thus, sDoFFI is not limited to laboratory-based samples but also characterizes biological and commercial surfaces. The technique holds potential in process control and optimization.
In case you are interested in sDoFFI, please contact me. Email
We can do service measurements and cooperate with you.
Contact Rüdiger Berger
Physics of InterfacesAckermannweg 10
55128 Mainz
Germany
Tel.: + 49 (0)6131 379114
Fax.: + 49 (0)6131 379100
Room: 2.122