Superhydrophobic surfaces are gaining more and more attention as new applications for them arises. For surface to be superhydrophobic, it has to fulfil two requirements. The static contact angle has to be over 150 degrees but in addition to that, the surface has to have a low contact angle hysteresis. For this reason, measurement of dynamic contact angles is especially important when superhydrophobic surfaces are studied.
There are two main methods for dynamic contact angle measurement; tilting cradle and a so-called needle method. Tilting cradle is fairly often used for dynamic contact angle measurements but can be troublesome for superhydrophobic surfaces. Placing the drop on superhydrophobic surface is somewhat difficult as the drop would prefer to stay in the needle. Also the drop rolls off the image very easily as the contact angle hysteresis is low. For these reasons most of the people prefer the needle method where needle is left in contact with the drop.
Watch the short webinar through the link below to see how contact angle measurements can be done in practice on superhydrophobic surfaces.
Susanna is an Application Scientist at Biolin Scientific. In her PhD thesis, she developed fabrication methods for a new type of inorganic-organic polymers. Microfabricated polymer chips were utilized as tool for biomolecule separation in analytical chemistry.