Low molar mass ionic liquid's modified carbon nanotubes and its role in PVDF crystalline stress generation

In this work, the question is whether the positive charge or the confirmation of side chain of an ionic liquid l-methylimidazolium bromide or the modified solid support multi-walled carbon nanotubes affects the heterogeneous crystallization of melt-crystallized polyvinylidene fluoride. The percentage (%) weight of polyvinylidene fluoride, ionic liquid and multi-walled carbon nanotubes were sequentially dissolved into DMF and stirred for 2 h at 40 degrees C. The homogeneous solutions were poured into petri-dishes to solidify. The samples P0, P1, P2, P3, P4, P5 were characterized via FTIR, SEM, DSC and XRD. The data obtained solidly supported the investigation. The concentration of ionic liquid was optimized according to the system employed. It was confirmed that multi-walled carbon nanotubes accelerate heterogeneous nucleation of polyvinylidene fluoride as usual, but the formed crystals are dominantly nonpolar alpha form. Incorporation of only ionic liquid results in depression of the polyvinylidene fluoride melting crystallization rate due to the inherent plasticity of ionic liquid but generates higher content of polar beta and gamma crystals. The structural spherulites were deformed in case of ionic liquid utilization. The ionic liquid's loaded solid supports multi-walled carbon nanotubes synergistically enhancing both nucleation and polar phase formation. The immiscibility and non-compatibility of the ionic liquid generated a unique stressed structure with delayed crystallization in the form of necklace-like structure on the composite surface clearly depicted from SEM data.