Water Shedding Angle: A New Technique to Evaluate the Water-Repellent Properties of Superhydrophobic Surfaces

A new technique is introduced to evaluate the wetting properties of superhydrophobic textiles which are not accessible by classical contact angle measurement techniques. The principle behind the new water shedding angle technique is the ability of a superhydrophobic surface to repel drops of water upon impact. In this sense it shows a strong reference to application and its results are easily understood in terms of water protection. The procedure is simple and straightforward and the experimental setup can be easily built or adapted to most available contact angle measurement systems. In view of the significant potential of superhydrophobic coatings for textile applications, the water shedding angle provides a reliable and comparable measure to judge the quality of a superhydrophobic textile in terms of water repellency. It constitutes a useful addition to existing techniques and has proven to be better suited to evaluate the wetting properties of superhydrophobic textiles than the contemporary methods presently in use.