Surface Science Blog

How to measure dynamic contact angles on superhydrophobic surfaces

Posted by Susanna Laurén on January 17, 2017

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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 video below to see how dynamic contact angles can be measured in practice.

  

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Read more

Durability of superhydrophobic surfaces – the biggest obstacle towards real life applications

 

Advances in Wettability Analysis for Superhydrophobic Surfaces

 

Topics: Contact Angle, superhydrophobic surfaces