Preparation And Characterization Of Anisotropic Particles Based On Polyvinylidene Fluoride

PVDF/P(St-co-MPS-co-AA) composite particles are synthesized through seeded emulsion polymerization by using poly(vinylidene fluoride)(PVDF) as seed and styrene(St), trimethoxysilyl propyl methacrylate(MPS) and acrylic acid as monomers. By tuning the polymerization temperature, the hierarchical surface morphology including adjustable sizes and number of the P(St-co-MPS-co-AA) protrusions nucleated onto the PVDF seed surface can be well controlled. Syntheses of other polymeric anisotropic particles are explored preliminarily via using other kind of monomers. We further study property and application of the PVDF/P(St-co-MPS-co-AA) composite particles.The morphologies of composite particles are characterized by scanning electron microscope(SEM) and transmission electron microscopy(TEM). We can propose a possible formation mechanism of PVDF/P(St-co- MPS-co-AA) composite particles, based on the SEM and TEM study results. The confined crystallization behaviour and the hydrophilicity of the PVDF/P(St-co-MPS-co-AA) anisotropic particles film are tested and characterized through Fourier transform infrared(FTIR), thermo-gravimetric analysis(TG), water contact angle, differential scanning calorimetry(DSC), and Wide angle X-ray diffraction(WAXD).The results show that the addition of AA and MPS plays important role in determining the formation of popcorn-like Janus and homocentric raspberry-like core-shell morphology. While the P(St-co-MPS-co-AA) copolymer nucleates on the surface of PVDF seed particles, the crosslinking reaction from the MPS hydrolysate prevents the copolymer bulges merging together to form homocentric core-shell structure, and the fusion of nanosized P(St-co-MPS-co-AA) protrusions each other provides a perfect coverage of the PVDF seeds. This results in a high efficiency of confined crystallization for PVDF in nanospheres with the larger core-shell ratio of the PVDF/P(St-co-MPS-co-AA) particles.In other systems, we have studied other kinds of monomer, e.g. vinyl chloride(VC), copolymerization of glycidyl methacrylate(GMA) or AA or butyl acrylate(BA) and St. And a crosslinking agent is directly added into the PVDF/PS system. The result show that the addition of the crosslinking agent will lower the mobility of the PS phase on the surface of PVDF.