Dynamic wetting characteristics of polymeric insulating materials

It is shown that surface condition does not appear to be a dominant factor in defining the amount of condensation forming on the surface of polymeric insulating materials such as ethylene propylene rubber and silicone rubber. The amount of condensation seems to be dominated by the bulk properties of the material such as specific heat capacity and density. This will mean that existing condensation models such as that used by Karady may be used to approximate the mass of water condensing on a polymeric surface. The structure of the condensation layers is very different among different materials and surface treatments. Appearance ranges from a completely wet film for a hydrophilic surface to a droplet layer consisting of uniform discrete droplets with drop separations of about one diameter for a simulated ideal hydrophobic surface. Surfaces with large contact angle hysteresis exhibit irregularly shaped drops with smaller inter-drop distances