Effect of poly(vinylidene fluoride) on solvation of NaSCN in PEO

The blend-based electrolyte, polyethylene oxide (PEO)-poly(vinylidene fluoride) (PVdF)-NaSCN, was prepared and characterized by FT-IR, X-ray diffraction (XRD) and differential thermal analysis (DTA) measurements at room temperature, and the effect of PVdF content on solvation and ion association was discussed over the content of 5-95%. It is shown that PEO has much stronger ability of solvation to NaSCN than PVdF does, indicating that the polymeric donor number is more important than its dielectric constant in solvating effect of polymer. However, PVdF can keep its semicrystalline nature and form microporous structure in blend-based electrolytes. These characters make PVdF not only enhance the mechanical stability of the electrolyte thin films, but also transform PEO crystalline phase into fully amorphous phase. Although PVdF can effectively disrupt the crystalline complex P(EO)3NaSCN, it does not affect the component of triple aggregations. In addition, the effect of PVdF content on ion association is also discussed in PEO-NaSCN electrolytes.