SiOxNy薄膜结构对气体阻隔性的影响

在聚合物表面沉积一层薄膜可以有效阻止氧气和水蒸气的渗透,目前比较常用的阻隔膜为氧化铝薄膜和氧化硅薄膜。氧化铝薄膜具有很好的气体阻隔性能,被广泛应用于食品包装;氧化硅薄膜也是比较流行的透明包装阻隔材料。近年来随着包装业的发展,对包装品阻隔性的要求越来越高,如要求更长的货架期。然而,目前所应用的氧化物阻隔膜已很难达到这一更高的要求。经研究发现,相对于氧化硅薄膜,类金刚石（DLC）是非常有前景的阻隔材料,特别是氮氧化硅（SiOxNy）薄膜,可以提供更高的阻隔性能。

Influence of Film Structure on Gas Barrier Properties of SiOxNy Films

SiOxNy thin films were deposited on PET substrates by dc magnetron sputtering under various nitrogen gas flow ratios, and the influence of the nitrogen gas flow ratio on the gas barrier performance was examined on the basis of local structure of SiOxNy.The surface morphology of the films was evaluated by FE - SEM and AFM observations.The local structure of SiOxNy was determined by FT - IR analysis and measurement of refractive index No obvious macro-defects,such as pinholes, were observed in the films and the surface morphology of all samples was similar.The film density increased with increasing nitrogen gas flow ratio during the deposition process.However,the gas barrier performance decreased with increasing nitrogen gas flow ratio.On the basis of FT - IR analysis,it was determined that the structure of the SiO_xN_y 1m was a random bonding model（RBM） structure and an increase in the nitrogen gas flow ratio caused an increase in hydrogen termination in the Si-O-N network.The degradation of gas barrier performance at a high nitrogen gas flow ratio is due to the discontinuous Si-O-N network caused by the hydrogen termination.