The limits of surface analysis with test inks

New application report about a comparative study from our laboratory

The quality when bonding, coating or printing material surfaces is substantially determined by the surface free energy (SFE) of the material. In this regard, contact angle measurement, for example with our Mobile Surface Analyzer – MSA, is increasingly replacing surface testing with test inks as a measuring method. There are good reasons for this, as Dr. Thomas Willers, Head of the KRÜSS Applications & Science Center, and his team demonstrate based on a comprehensive study.

Dr. Willers and his colleagues determined the SFE of a large number of materials based on contact angle measurements. They compared the results with those from their ink tests and identified major differences in many cases. Specifically for materials with high polar fractions of the SFE, the contact angle method gave significantly higher values than the test ink method. The scientists were able to show that the ink tests seldom detected differences in the SFE when these originated from the polar fraction. In particular, the activation of some plastic surfaces by means of plasma treatment could not be adequately characterized using the ink test method.

Download the full application report on this subject.