Effect of surface fluorination on space charge behavior in multilayered polyimide films

The existence of space charge has a great effect on breakdown characteristic and is the main reason leading to dielectric breakdown. Fluorination as change the chemical component in surface layer of polymers should give rise to the corresponding change in electrical properties of the surface layer thus influence the charge injection from electrodes. This paper presents a study aimed at clarifying the effect of fluorination on space charge behavior in multilayered polyimide films. The surface chemical compositions of the fluorinated films together with the original (unfluorinated) film as a reference were characterized. The space charge distributions in multilayered polyimide Films were measured using the pulsed electro-acoustic (PEA) method. Obtained results show that the space charge distribution of multilayered film stacking with five fluorinated samples is quite different from that of multilayered film stacking with five untreated samples. It is also suggested that the fluorination can significantly suppression the injection of space charge.