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.
Check the webinar below to see how dynamic contact angles can be measured in practice.
A self-cleaning surface is any surface with the ability to readily remove any dirt or bacteria on it. Self-cleaning surfaces can be divided into three different categories; superhydrophilic, photocatalytic and superhydrophobic.
Blood-repellent surfaces are needed in medical devices that come in contact with blood. The traditional approach has been the use of antithrombotic surface treatments However, these coatings are prone to eventually wear-off. Superhydrophobic surfaces have been proposed as an alternative solution.