Ageing of chemically modified poly(vinylidene fluoride) film: Evolution of triple carbon-carbon bonds infrared absorption

The paper presents the results of the combined investigation of changes in the poly(vinylidene fluoride) (PVDF) structure caused by chemical carbonization and subsequent long-term ageing, as one of the most promising ways to synthesize the 1D modification of chemically pure carbon, carbyne. For the first time, the ageing process of PVDF was monitored during extremely wide time-frame from 19 to 500000 min. The evolution of PVDF molecular structure was investigated experimentally by infrared and X-ray absorption spectroscopies. As a result, non-monotonic variation of triple carbon-carbon bonds infrared absorption in the course of long-term ageing was revealed, as well as new aspects of PVDF carbonization. The series of appropriate molecular complexes were modeled, for which characteristic frequencies and absorbance intensities in the IR spectra were simulated by the DFT-LDA method and applied to interpret the results of the experimental study. •PVDF structure changes caused by chemical carbonization and subsequent long-term ageing were elucidated.•IR and X-ray absorption spectroscopies together with DFT-LDA method were used.•Evolution of triple C–C bonds IR absorption in the course of ageing was revealed.•IR spectra of model molecular complexes were simulated.•New aspects of PVDF carbonization were revealed.