The vacuum surface flashover performance of insulators is the focus of electrical engineering. Consequently

we employed CF

4

plasma excited by a dielectric barrier discharge system for surface modification of cross-linked polystyrene（CLPS）. The surface properties of CLPS were investigated

including water contact angle measurements

surface morphology observation by atomic force microscopy（AFM）

and surface composition analysis by X-ray photoelectron spectroscopy（XPS）.Meanwhile

the flashover performance tests of CLPS were also carried out

the influence of nanoscale surface microtopography and surface fluorine were discussed. Results show that CF

4

plasma can change the surface morphology of the material and fluorinate the surface

and the flashover voltage of v

acuum surface of CLPS can be improved by more than 50% by this method. Surface microtopography parameters Ra of the sample first increases then decreases as the treatment time increases and the surface protuberance increases; fluoride groups are introduced into the material surface and mainly in the form of C—F. The increase of surface microtopography parameters Ra and the introduction of C—F bond lead to the increase of vacuum flashover voltage.