Improving the oxygen barrier properties of PET polymer by radio frequency plasma-polymerized SiOxNy thin film.

Abstract Plasma-polymerized silicon oxynitride (SiO x N y) oxygen barrier thin film was deposited on polyethylene terephthalate substrate by plasma enhanced chemical vapor deposition at low temperature. The deposition reactor utilizes capacitively coupled plasma operating at radio frequency (13.56 MHz). Nitrogen incorporation during the polymerization leads to a SiO x N y dense film with low defects which assists to improve the oxygen barrier properties. The gas mixture of tetraethyl orthosilicate as organosilicon precursor with oxygen and nitrogen gases was used to deposit the transparent polymerized SiO x N y thin films. The effects of nitrogen flow rate on deposition rate, refractive index, surface morphology, surface wettability, chemical structure and binding composition and oxygen permeability of the barrier films were investigated. Moreover, the plasma parameters were monitored by optical emission spectroscopy. SiO x N y oxygen barrier films showed 89–91% transparency. Under the optimal deposition conditions the minimum oxygen permeability of 0.08cm3/cm2day bar was obtained. Highlights • Oxygen barrier films are obtained in low RF power and low temperature. • Transparent gas barrier is obtained which makes it possible to check inside a package. • Nitrogen content, ordered structure and low impurity led to very low O 2 permeability. • Low value O 2 permeability achieved which is favorable for OTFTs and drug packaging. • The lowest value of O 2 permeability obtained is 0.08cm3/cm2day bar. [ABSTRACT FROM AUTHOR]