The supramolecular organization of PVDF lamellae formed in diphenyl ketone dilutions via thermally induced phase separation

The crystallization of poly(vinylidene fluoride) (PVDF) during thermally induced solid–liquid phase separation leads to supermolecular structures in PVDF/montmorillonite (MMT)/diphenyl ketone dilutions with various poly(methyl methacrylate) (PMMA) contents. The presence of MMT had a significant nucleation enhancement on the β-PVDF crystals along with the MMT surfaces, and subsequently the α-PVDF crystals formed between MMT layers. The mechanism of the PVDF crystallization in the dilution was studied by DSC, POM, FTIR, and SEM results. A small amount of PMMA incorporation (0.3 wt%) improved the dispersion of MMT in the mixture, leading to the highest nucleation effect on the PVDF crystals. This result proves that PMMA chains acted as a good interfacial agent for PVDF and MMT nanoparticles. A well-interconnected supermolecular morphology formed in the dilutions resulted in a higher tensile strength. When the PMMA content was over 1.5 wt% in the dilution, the excessive amorphous PMMA chains would hinder the crystallization of PVDF; subsequently, less interconnected PVDF lamellae structures lowered the tensile strength.