Deposition features and wettability behavior of fluoropolymer coatings from hexafluoropropylene oxide activated by NiCr wire

The paper presents the results of the Hot-Wire Chemical Vapor Deposition of fluoropolymer films from C3F6O precursor gas, activated by NiCr wire catalyst mesh, at varying deposition process parameters. The temperature of activator wire is varied within the range of 580-900 degrees C, precursor gas pressure is changed within the range of 4-1333 Pa, and the temperature of the substrate is changed from 20 to 400 degrees C. The different surface structures of fluoropolymer coatings are obtained by changing the deposition parameters. The morphology and composition of the films and the growth rate were investigated by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy methods. We have measured contact angle, contact angle hysteresis, and surface free energy of the resulting fluoropolymer coatings. The surface structure of the coatings is shown to have a significant effect on the coating wettability. One of the main results is that the increasing of the activating mesh wire temperature leads to increasing of the contact angle and allows us to obtain superhydrophobic coatings. We have shown that the wettability properties can be regulated by deposition parameters. Experimentally determined optimal values of deposition parameters ensure uniform deposition of the film with superhydrophobic properties.