Characterization of composite SiO _x/polymer films deposited on pet substrates by RF reactive magnetron sputtering

Composite SiO _x/polymer films have been prepared on polyethylene terephthalate (PET) substrates by radio frequency (RF) reactive magnetron co-sputtering, from which two balanced magnetrons are equipped with silica and dicyclopentadiene dioxide cured with maleic anhydride (DCPD/MA) targets. Morphology and composition of the deposited composite films have been analyzed by means of AFM, FTIR, and XPS. The influences of preparation procedure parameters, primarily including RF power densities and the ratio of RF powers delivered to the two targets, on the obtained films properties such as surface roughness, water vapor/oxygen transmission rate and flexibility have been investigated. As P _DCPD/MA/P _SiO2, the ratio of RF powers delivered to the individual target changed from 0.13 to 7.5, the roughness of films decreases from 2.793 nm down to 0.9 nm and the numbers of cracks produced in the films after folding are reduced dramatically. At the ratio of RF power of 3, higher RF power densities and lower work pressure have better performance in preventing the permeation of water vapor and oxygen. The minimum transmission rates of water vapor and oxygen are 0.26 g/m ²/24 h atm and 0.38 cc/m ²/day atm, respectively.