Transparent Superhydrophobic Polytetrafluoroethylene Films Prepared By Radio Frequency Magnetron Sputtering

Super-hydrophobic film have been extensively studied in the past two decades due to its wide practical value and important research significance.Super-hydrophobic film was widely used for self-cleaning,anti-icing,anti-fog,anti-corrosion,fluid,biomedicine,oil-water separation and so on,and then extended to numerous new research fields such as oil,sparse,hydrophobic anti-icing,hydrophobic anti-corrosion etc.It can be said that the superhydrophobic preparation process,material selection,modification method,theoretical model are all the cornerstone of these new application research fields,with important research significance.However,on the smooth surface such as glass surface,one step preparation of superhydrophobic film has been a difficult point for a long time.The usually used methods exist issues such as environmental pollution,complex steps’ operation,poor film-base bingding,water droplets’ stiction etc.In this paper,a transparent superhydrophobic polytetrafluoroethylene film was prepared on the glass substrate by one-step RF magnetron sputtering technique,which was friendly to the environment,low cost,simple operational and excellently effective.The properties of the films were investigated by contact angle tester,surface profiler,scanning electron microscope,X-ray photoelectron spectroscopy,freezer,UV-Vis spectrophotometer and high-speed camera.The results show that the film prepared by this technology has low-temperature resistance,the contact angle of the membrane is 173±2.3 ° and the rolling angle is 2.9 °,and the effect of "lotus leaf effect" is attainable.Such film has a transmittance of 90% for the macroscopic 555 nm,and the common transmittance of film and substrate is higher than 80%.The film is colorless and has good transparent superhydrophobic properties.The films contain NaF,CF2 and CF3.In the process of heating sputtering,fluoride ions are etched to the glass substrate.The fluorine atoms are chemically bonded to the substrate,which enhances the bonding force between the film and the substrate.With the growth of sputtering time,the content of CF3 increases,makeing the film have very low surface energy and reduceing its rolling angle.The heating makes the sputtering PTFE have a new film forming mechanism.During the sputtering process,the volatilization of PTFE leaves the pores and forms a micro-nanostructure with the PTFE islands formed during the cooling process.Such structure can store air and enhance the hydrophobicity of the film.The hole structure mainly increases the contact angle,while the size and intensity of the island primarily contributes to the reduction of the rolling angle.The pores and the irregular structure of the film store a lot of air,which can elastically collide with the water droplets,so that the water droplets completely deformed,and retains a lot of energy during the rebound,forcing the water droplets bounced on the surface several times.The results show that the polytetrafluoroethylene film prepared by magnetron sputtering process is excellently hydrophobic,transparent and with high bounce performance,and can maintain its superhydrophobic performance at low temperature,possessing an extensive application prospect.