New reference book contribution on test inks from our scientific team

Peer-reviewed article by KRÜSS in a book on adhesion published by Dr. Kash Mittal

The second volume of Advances in Contact Angle, Wettability and Adhesion published by Dr. Kash Mittal appeared a few weeks ago. Dr. Mittal is a globally renowned expert in adhesion research, author of numerous reference books and publisher of the journal Reviews of Adhesion and Adhesives. He is also known to the professional world through his successful Course on Adhesion Science and Technology, which he will hold in collaboration with us in Hamburg for the second time early in 2016.

His new volume focuses on basic investigations into adhesion and wetting modification. The third part is dedicated to the connection between surface free energy (SFE) and adhesion, with our investigation Why Test Inks Cannot Tell the Whole Truth About Surface Free Energy of Solids.

The article is a comparative study of test inks and contact angle measurements based on a number of materials. It is an extended, peer-reviewed version of our application report AR272. It has been shown that test inks cannot be used to differentiate whether wetting behavior is determined by differences in the total SFE or the polar fractions. While for non-polar plastics results with test inks still correlate well with the SFE derived from contact angles, with polar surfaces large deviations between the two methods occur. The increase in the polar fraction of the SFE due to plasma treatment, in particular, could be reliably demonstrated with the help of the contact angle, while the test inks responded virtually indifferently. The test ink method is therefore questionable for one of its most important applications.

Source: M. Jin, F. Thomsen, T. Skrivanek and T. Willers, Why Test Inks Cannot Tell the Whole Truth About Surface Free Energy of Solids, in: K. L. Mittal (Ed.), Advances in Contact Angle, Wettability and Adhesion Volume 2 , Hoboken, New Jersey and Salem, Massachusetts 2015, P. 419-438.