Reducing the wettability

To make a surface non-wettable, its surface energy must be smaller than the surface tension of the respective liquid. Surface energy can be reduced by various surface coatings:

• Plasma polymerisation of HMDSO creates surfaces with a low surface energy which not only are water and dirt repellent but also protect plastic surfaces.
• Plasma polymerisation of gaseous fluorocarbons can create PTFE coats with ultra-hydrophobic and lipophobic properties.
• Targeted oxidation of metal surfaces not only protects from corrosion but also reduces the surface energy.

PTFE coats are primarily used on textile surfaces to make them hydrophobic and this waterproof and dirt-repellent.