Study On Surface Modification Of PET Film By Dual-source Excitation DBD

PET(Polyethylene terephthalate)film is being extensively used in food packaging,solar panels,and insulation materials for high-voltage equipment such as transformers due to its high transparency and excellent electrical insulation properties.But,in the atmospheric environment,the PET film is easy to accumulate dust and fog on the surface which affects transparency,and it easily accumulates charge on the surface under the DC electric field environment which will increase the risk of surface flashover and reduce the safety of electrical operation.Therefore,in response to the above problems,this article selects dual-source excitation DBD surface modification technology to treat PET film,realizes the regulation of PET film surface wettability and improves surface charge accumulation and dissipation characteristics,thereby improving its DC withstand voltage performance.Combined with optical,chemical and electrical detection and analysis,the physical morphology and chemical group changes on the surface of the modified PET film were explored,and the main mechanism of dual-source excitation of the surface wettability and charge dissipation characteristics of the DBD modified PET film was determined.The main research contents of this paper include:Firstly,a three-electrode structure experimental device was designed,which can realize the cooperative excitation mode of radio-frequency power source and pulse power source,two-layer dielectric barrier discharge.The device uses a common ground connection method,the upper radio-frequency power source and the lower pulse power source shared one ground.Each of them was an independent loop,which reduces the impact of coupling between two power sources.The pulse area discharge promotes the occurrence of the radio-frequency area discharge,and the active particles produced by the radio frequency area discharge enhance the stability and uniformity of the pulsed area discharge.Secondly,a dual-source excitation platform for DBD modified PET film surface wettability was set up,Argon(Ar)is the working gas,hexamethyldisiloxane(HMDSO)was used as a precursor.The results show that the static water contact angle of the PET film increases from 61°to151°,showing super-hydrophobic characteristics.Meanwhile,after being placed in the atmosphere for 15 days,the static contact angle of water droplet deposited on the sample surface is reduced to only 4°,initially showing good anti-aging performance.Then,another dual-source excitation platform for DBD modified PET film surface dielectric properties was set up,Ar and CF₄(carbon tetrafluoride)as working gas.Through the analysis of the surface physical morphology and chemical groups,it is determined that the etching effect of Ar/CF₄ plasma causes an increase in roughness,and successfully doped fluorine into the chemical groups on the surface of the PET film,enhance its dielectric properties.Finally,the influence of dual-source excitation DBD modified PET film conditions on the surface charge accumulation,decay performance of the PET film and the electric field type on the DC surface flashover performance are explored.The results show that the coordinated excitation mode of radio-frequency power source and pulse power source,CF₄ gas flow rate of 1 sccm,and treatment time of 2 min,the surface flashover field strength of the PET film can be increased by up to 24%,and the surface potential decay characteristics have a good anti-aging performance.This paper provides a simple,direct,and efficient treatment method for the surface functionalization of PET film to realize its self-cleaning or anti-fogging,or to improve the surface flashover insulation characteristics.Besides,this treatment method is also suitable for other thin films or solid media material.