Augsburg 2006 – wissenschaftliches Programm

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P: Plasmaphysik

P 13: Niedertemperaturplasmen / Plasmatechnologie 4

P 13.1: Fachvortrag

Dienstag, 28. März 2006, 14:45–15:15, 1002

Analysis of SiO₂-like Plasma Polymerized Barrier Layers — •M. Leins, M. Walker, A. Schulz, U. Schumacher, and U. Stroth — Universität Stuttgart, Institut für Plasmaforschung, Pfaffenwaldring 31, D-70569 Stuttgart

Today polymers are used more and more for food packaging materials because of their numerous advantages such as low specific weight and environmental compatibility. However, these food packaging materials also show some disadvantages: soft drinks may lose CO₂ and atmospheric oxygen may penetrate from outside and oxidize constituents of the food. By coating the inside of the packaging with a silica like barrier, these negative effects are reduced while maintaining all advantages of plastic packaging. This study covers the deposition of such SiO₂-like barrier layers on polyethyleneterephthalate (PET, thickness: 26µ m) using an Electron Cyclotron Resonance (ECR) heated microwave plasma in pulsed mode. The plasma source allows a homogeneous deposition of about 100 nm thickness on large areas (several dm²). An organo-silicon compound – hexamethyldisiloxane (HMDSO) – and oxygen were utilized as deposition gases. The external parameters aspect ratio, gas mixture and thickness of the layer were varied. The oxygen permeation properties were measured with the carrier-gas method as a function of time. For a pulse pause ratio of 500µ s to 500µ s and a gas mixture of O₂ to HMDSO of 20:1 the permeation could be reduced by more than one order of magnitude. To explain the results, the layers were characterized by infrared absorption spectroscopy (FTIR) and scanning electron microscopy (SEM).