Film deposition in a radial flow reactor by plasma polymerization of hexamethyldisilazane

Polymeric substrates can be coated at low temperatures by means of an electric discharge fed by organic gases. Since both the composition and the structure of the deposited material can be varied in a wide range by the choice of starting compound and deposition conditions, the properties of the coatings can be adjusted specifically to fulfill many required demands. After a general introduction of the deposition method, a typical deposition apparatus is described and an optimization procedure of the deposition process is proposed.The intermediate position of plasma polymerized materials between common polymers and amorphous solids is demonstrated for films from hexamethyldisilazane. Based on the assumption of a continuous random network structure the density of covalent bonds and the total volume fraction of micro-voids can be evaluated and compared with application relevant properties such as mechanical stiffness and gas permeability.The model of a continuous random network structure may be valid for plasma polymerized material in general.