MORPHOLOGY AND GAS BARRIER PROPERTIES OF THIN SiOx COATINGS ON POLYCARBONATE: CORRELATIONS WITH PLASMA-ENHANCED CHEMICAL VAPOUR DEPOSITION CONDITIONS

Plasma-enhanced CVD of SiOx coatings on thermoplastics provides a viable route for production of transparent composite materials with high fracture toughness and high gas barrier properties, which are important considerations in the food packaging and biomedical device industries. By examining several series of systematically varied SiOx/polycarbonate composites, design correlations between coating characteristics (thickness, density, surface roughness, and O2 transmission) and deposition conditions (time, power, pressure, and flow rates) have been identified. Of particular interest is the observation that the thermal activation energy for O2 permeation through these composites increases (by up to 17 kJ/mol) as their barrier efficacy increases. 50 refs.