Polytetrafluoroethylene (PTFE), polyhexafluoropropylene (PHFP) and polychlorotrifluoroethylene (PCTFE) were heated to their decomposition temperature in a high vacuum. The emitted fragments passed an electron cloud, condensed on a substrate and formed fluoropolymer film. Growth rate of PTFE and PHFP films increased up to a factor five in the presence of the electron cloud. Mass spectrometry revealed changes in the mass spectra of fragments generated by thermal decomposition only and formed under electron activation. The observed changes were different for each fluoropolymer. Infrared spectroscopy (IRS) showed that the structure of the films was close to the structure of the bulk polymers. Atomic force microscopy (AFM) has revealed different morphologies of PTFE, PHFP and PCTFE films, suggesting a Volmer–Weber growth mechanism for PTFE and PHFP but a Frank-van der Merwe one for PCTFE. All films were smooth at nanoscale and transparent from ultraviolet to near-infrared region. Additional radio frequency (RF) plasma ignited in the emitted fragments at a low pressure increased mechanical characteristics of the films without losing their optical transparency and smoothness.
Thin polytetrafluoroethylene (PTFE) films are produced by deposition from a gas phase by two methods: electron-enhanced vacuum deposition (EVD) and EVD + low-temperature plasma (LTP). Structure, morphology, and composition of the films are studied by IR spectroscopy, atomic force microscopy, and X-ray photoelectron spectroscopy. They are close to the structure of bulk PTFE. The roughness of the films' surface is changed with gas pressure and LTP power variations. Films are transparent from UV to near-infrared regions. Refractive and extinction indices and their anisotropy are measured by spectral ellipsometry. They are tuned by variations of deposition conditions. Hardness and Young modulus of the films are increased if EVD + low power LTP is used for film deposition. Use of EVD + LTP also increases thermal stability of the films. Contact angle of the films corresponds to the bulk PTFE. The PTFE molecules oriented are preferentially in perpendicular direction to the substrate surface.
Fluoropolymers (FP) are materials with a combination of excellent physical and chemical properties which make them useful in various industries. Thin films of these almost insoluble polymers were deposited with decomposition-evaporation of bulk FP in a vacuum. The pretreatment of the evaporated FP, the pressure of the emitted gas, the activation with accelerated electrons, the additional radio frequency (RF) plasma and the external magnetic field had complex effects on the morphology and relief of polytetrafluoroethylene (PTFE) films. Thin PTFE films with a roughness from 2 to 100 nm were produced. A PTFE film grown in a magnetic filed had nanoworms on its surface. The hardness of PTFE films was increased using low power RF plasma during deposition. The hardness of polychlorothrifluoroethylene (PCTFE) thin film was significantly smaller, whilst the relief of PCTFE films was rougher than that of PTFE films. A conformal PTFE coating was deposited on a nanostructured plastic surface using PTFE evaporation with electron activation and low power RF plasma.
VOx films deposited using the multistep method have been investigated. These films were deposited by repeating the two-stage method of low-temperature deposition – low-temperature annealing. The structure and characteristics of VOx thin films have been studied. Taking into account the obtained results, theoretical modeling of the structure was performed and the parameters of the metal-insulator transition have been calculated.
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