Influence of isothermal heat-treatment duration on magnetic and structural properties of chemically carbonized poly (vinylidene fluoride) derivatives

Relevance of the work: Modern science and technology show interest to use of low-dimensional and nanodimensional materials based on carbon. One of the most prospective materials for synthesis of similar structures is poly (vinylidene fluoride). The same amount of fluorine and hydrogen in polymeric chains of this material allows achieving high extent of its dehydrofluorination by elimination of HF molecules. At gradual penetration of dehydrofluorinating chemical reagents in depth of a poly (vinylidene fluoride) film, carbon heterolayers are formed on its surface. They differ in residual fluorine content and electric conductivity. Such heterostructures with flexible polymeric basis substrate can be demanded by modern microelectronics. Therefore study of their physical and chemical properties seems to be urgent. The main aim of the research is to study the effect of isothermal annealing duration at 250 °C on magnetic and structural characteristics of poly (vinylidene fluoride) samples partially dehydrofluorinated via a chemical way. The methods used in the study: ESR-spectroscopy, differential thermal analysis, thermogravimetric and differential thermogravimetric analysis, X-ray diffraction. The results: The authors have developed the method for producing a new magnetically active carbon material on a poly (vinylidene fluoride) film surface. The parameters of ESR spectra of poly (vinylidene fluoride) samples partially dehydrofluorinated via a chemical way were measured. The samples were subjected to subsequent heat treatment at 250 °C with various duration of isothermal annealing. Based on the data of differential thermal analysis the assumptions are drawn on possible mechanism of regular elevation in paramagnetic centers content at increase in time of isothermal annealing.