The composition of radiation curable varnishes and their influence to roughness of smoothing layers

 
The surface of polymer substrates has to be adapted very often to later applied technologies. For instance PVD coatings for permeation barrier purposes need very low roughness. Therefore so called smoothing layers made by wet chemical methods are coated onto the polymers. Radiation curing can be used to ensure very high productivity at very low temperature stress. Varnishes cured by electron beam are used here to deposit the smoothing layers. Their chemical composition will be modified to influence the roughness of the respective layers at micrometer and nanometer scale. The results of measurement methods like profilometer, white light interferometry or atomic force microscopy will be presented. In a second technology step permeation barrier layers will be deposited by sputtering onto the smoothing layers. The relation between permeation barrier and roughness will be discussed.