Hydrophobicity Of Polytetrafluoroethylene Film Depositied By Gas Phase Method

Wetting, a kind of solid surface characteristic, was a common interface phenomenon of nature and human life. In recent years, hydrophobic and superhydrophobic materials had been received great attention of researchers due to its potential functional applications. At present, most studies utilized wet process to prepare superhydrophobic surface. However, wet process does not apply to prepare polytetrafluoroethylene PTFE film due to PTFE is almost insoluble in any reagents. The aim of this study was to deposite PTFE hydrophobic film by the method of low power electron beam evaporation process, the main results and conclusions in this thesis were summarized as follows:The method of low power electron beam evaporation was used to deposite PTFE films on the ceramic substrates. The effect of preparation technology and basement properties on the morphology and wettability of PTFE film were stduied. The results showed that all surfaces of thin film prepared appeared hydrophobicity. Meanwhile, sulfuric acid concentration, etching time and deposition time had a significant impact on topography, roughness and hydrophobicity of film surface.In addition, ceramic and slide substrates were choosen as the substracts to prepare PTFE films, and calculated the surface energy. We found surface properties also impacted the wettability of membrane as well as the roughness, but the effect of surface energy on the wettability of membrane was more apperent than roughness.The PTFE superhydrophobic surface was prepared successfully on the copper substrates etched by oxalic acid through changing the technology parameters. The contact angle reached153.34°and the rolling angle was near to0°, which showed excellent superhydrophobicity. The analysis further proved that the modification of low surface energy material was the main factor to make surface superhydrophobic.The Cu films, prepared by magnetron sputtering method, were choosen as the substrates. These substrates were treated by annealing or H2O2solution, respectively, then prepared Cu/PTFE composite membrane on.it. The effect of technology parameters on surface topography, roughness and hydrophobicity of composite membrane were studied. The results showed that the Cu film surfaces treated by H2O2solution formed nanorod structure with larger roughness. After deposited PTFE on it, the contact and rolling angle of Cu/PTFE composite membrane were155.17°and2°respectively, showed excellent superhydrophobicity.The polymethylene (PE)/PTFE composite membrane were prepared on copper substrates by electron beam evaporation method, and studied the impact of thickness of PE transition layer on adhesion and surface hydrophobicity of composite membrane. The results showed that the hydrophobicity of composite film deposited on copper etched by oxalic acid was better than not etched. At the same time, adhesion was negatively correlated with the contact angle, smaller the adhesion was, larger the contact angle was, and the hydrophobicity was also better. It explained that a certain thickness of PE transition layer can obviously reduce the surface adhesion force, thus enhanced hydrophobicity.