If gases are to be evacuated from fluids without simultaneous liquid transport or if electronic systems are to be ventilated, either naturally hydrophobic or for this purpose hydrophobic filter materials are suitable. Due to the large difference between the surface energy of the highly porous body and the surface tension of the liquid, large contact angles are created on the contact surfaces, which prevent the liquid from penetrating the porous material.
Classical areas of application for water-repellent porous materials are:
The naturally hydrophobic polyethylene (Siperm HP) is suitable for applications in the temperature range up to 70°C. For higher temperature ranges hydrophobized bronze (Siperm B) or hydrophobized stainless steel (Siperm R) are available.