Glossary of surface technology
Modifying the surface tension
Increasing or reducing the surface tension (resp. surface energy) of solid surfaces is one of the primary applications of plasma technology. High surface tension provides for:
- good wettability by liquids and thus
- good adhesion of paints, inks, adhesives, solders
- good filtering properties of porous materials
Low surface tension provides for:
- water-repellence and thus
- water-proof fabrics
- non-soiling and self-cleaning surfaces
- no attack by reactive liquids
- Epilamisation: prevents dissolving of lubricating oils
High surface tension is achieved by:
- Removal of separating substances by plasma cleaning
- Removal of oxide layers on metals, in particular by treatment in a hydrogen plasma
- Plasma activation by generation of polar groups, in particular oxygen bonds in the oxygen plasma
- Plasma coating by plasma polymerisationof hydrophilic coats, in particular polyvinyl acetate
Low surface tension is achieved by:
- plasma coating with hydrophobic polymers, in particular by using fluorine monomers as a process gas and polymerisation to PTFE-like coats or HMDSO and polymerisation to quartz-like coats.
