FTIR studies of DMF plasticized polyvinyledene fluoride based polymer electrolytes

FTIR studies of the polymer polyvinyledene fluoride (PVDF), plasticizer dimethyl formamide (DMF) and their mixtures with lithium tetrafluoroborate (LiBF4) were carried out. LiBF4-DMF spectra for various salt concentrations showed shifting of the band at 659 cm (- 1) to higher wavenumber at 680 cm (- 1). The band at 659 cm (- 1) represents the O=C-N group of DMF. The interaction is between the Li cation and the oxygen atom of the O=C-N since the IR spectrum did not show any shift in the C-N symmetric stretching band due to Li-N interaction. The splitting of the C-N symmetric stretching vibration of the plasticizer into a doubler at 860 and 880 cm(-1) is evidence of plasticizer-polymer interaction. With increasing PVDF content the intensity of the bands at 1257, 1093 and 1063 cm(-1), assigned to C-N asymmetric and CH3 rocking (out of phase/in phase) vibrational modes of DMF, changes and shifts to lower wavenumbers. PVDF and LiBF4 interaction is weak and is shown by the broadening and shifting of the bands corresponding to PVDF. (C) 2000 Elsevier Science Ltd. All rights reserved.