The wetting characteristics of PTFE particulate composites

A new type of water repulsive material was found to exhibit contact angles of more than 150 degrees. This particulate material is a composite consisting of low molecular weight PTFE particles dispersed in an appropriate binder. In order to explain the extraordinary wetting properties of these water repulsive particulate composites, their behavior has been analyzed on the basis of the Wenzel equation which takes into consideration surface roughness and the Cassie equation which considers heterogeneous surfaces. The analysis demonstrates that contact angles of 150 degrees are possible and identifies the conditions under which such high contact angles are possible.