Diffusion of a liquid or gas through a solid. Most thermoplastic materials used for production of vessels and containers at least are permeable in a minor degree for many substances. This can be avoided by barrier layers coated to the inside of these vessels. Plasma coating of barrier layers in a low pressure plasma is a perfect method to avoid permeation because cavities and caverns are accessable for low pressure plasma.

On a Tetra 2800 low pressures plasma system barrier layers are coated to the inside of containers to avoid permeation of aggressive substances.