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The overall crystallization kinetics and spherulite morphologies of miscible poly(ethylene oxide)(PEO)/1-butyl-3-methylimidazolium hexafluorophosphate([BMIM][PF_6]) mixtures were studied by differential scanning calorimetry(DSC),polarized optical microscopy(POM) and rheological measurements. The finer crystal structures were further detected by wide angle X-ray diffraction(WAXD) and small angle X-ray scattering(SAXS). Crystallization of PEO is largely suppressed by [BMIM][PF_6] addition especially at higher ionic liquid(IL) concentrations above 20 wt%. Both the overall crystallization rate and the spherulite growth decrease with the increase of IL content and crystallization temperature; however, the crystallization mechanism keeps unchanged as evidenced by the similar Avrami exponent n and WAXD results. The addition of [BMIM][PF_6] could induce more nuclei to some extent, but the induction time of crystallization is evidently prolonged,and a linear to non-linear transition of the spherulite growth(R ∝ t to R ∝ t~(1/2)) can be observed. At higher IL concentration,the spherulite texture changes apparently from particular serrated to branch surface due to the diffusion-controlled growth and the dilution effect, which also as a main factor contributes to the increasing trend of the long period of crystals.
The overall crystallization kinetics and spherulite morphologies of miscible poly (ethylene oxide) (PEO) / 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM] [PF_6]) were obtained by differential scanning calorimetry The finer crystal structures were further detected by wide angle X-ray diffraction (WAXD) and small angle X-ray scattering (SAXS). Crystallization of PEO is largely suppressed by [BMIM] [PF_6] ionic liquid (IL) concentrations above 20 wt%. Both the overall crystallization rate and the spherulite growth decrease with the increase of IL content and crystallization temperature; however, the crystallization mechanism keeps unchanged as evidenced by the similar Avrami exponent n and WAXD results. The addition of [BMIM] [PF_6] could induce more nuclei to some extent, but the induction time of crystallization is evidently prolonged, and a linear to non-linear transition of the sphe At higher IL concentration, the spherulite texture changes apparently from the serrated to branch surface due to the diffusion-controlled growth and the dilution effect, which also as a main factor contributes to the increasing trend of the long period of crystals.