The investigation of the structural change and the wetting behavior of electron beam irradiated PTFE film

Abstract

AbstractThe effect of electron beam (EB) irradiation on polytetrafluoroethylene (PTFE) film was studied in air at room temperature. The structural changes of the PTFE film irradiated by EB were determined by Fourier transform infrared (FTIR) and X-ray diffraction (XRD). The morphological changes on the film surface were described using scanning electron microscopy (SEM). The surface hydrophilicity of the modified film was characterized through water contact angle measurement. The results show that scission of the chain on the surface of PTFE film was induced by EB irradiation. The atomic ratio of F/C decreased and the atomic ratio of O/C increased. The surface roughness of the irradiated sample increased. In the case of irradiation in the presence of residual air, carboxylic acid fluoride groups appear and can hydrolyze to carboxylic groups in the surface-near regions. These polar groups significantly reduced the hydrophobicity and oleophobicity of the PTFE film and consequently cause the decline of the water contact angle of the film surface. XRD analysis reveals an increase of the crystallite size of PTFE along with the increasing time of the irradiate.