Properties of SiO_x/PET Thin Films Prepared by RF Magnetron Sputtering

Abstract

The SiOx thin films for food packaging were deposited by RF magnetron sputtering physical vapor technology on the substrates of 20μm polyethylene terephthalate (PET) by using a pure SiO2 target. The molecular structure of thin film surface composition were detected and analyzed by Fourier transform infrared spectroscopy (FTIR); and the barrier properties of the films were examined by MOCON water vapor permeability testing instrument, also，the relationship maps between permeability and process parameters were drew and the process parameters were optimized; The mechanical properties of thin films were tested by electronic tensile testing machine, and the curves of the relationship between the mechanical properties and process parameters depicted. The SiOx/PET thin films of the lowest water vapor permeability were prepared under the pressure of 7.5×10-3 Pa, the sputtering pressure of 0.23 Pa, the deposition time of 30min and the sputtering power of 1500W. The yield strength increased 4 times and elastic modulus increased 3 times when the water vapor permeability of the SiOx/PET thin films rose about 10 times of the blank.