Silicon oxide barrier coatings deposited on polymer materials for applications in food packaging industry

Deposition of SiO_x layers by low-pressure microwave plasmas is an excellent means to add missing barrier functionalities to cheap and material-saving homo-polymeric materials that will increasingly replace expensive multi-layer polymer food packaging. SiO_x coatings were deposited in an ECR plasma process on polyethyleneterephthalate (PET) foils using two different precursors, HMDSO and HMDSN. O₂ transition rates of less than 1 cm³ (m^-2·24 h ^-1·bar^-1) were obtained for the best performing SiO_x coatings deposited from O₂/HMDSN gas mixtures. First ECR plasma deposition tests on polypropylene (PP) trays show the high barrier potential of SiO_x coatings even on three-dimensional polymer food packaging.