Investigations Of Morphology And Formation Mechanism Of Asymmetric Particles Based On PVDF Synthesised By SET-LRP

Asymmetric poly(vinylidene fluoride)/polystyrene(PVDF/PS) composite latex particles with controllable morphologies were prepared using one-step soap-free seeded emulsion polymerization, i.e., surface-initiated single electron transfer living radical polymerization(SET-LRP) of styrene(St) at the surface of PVDF seed particles. And dialytic PVDF latex particles were as seeded latex and St was monomer. And then the amphiphilic copolymers PVDF/PS-co-PDMAEMA were synthesized with the observed PVDF/PS with living end groups as macroinitiator.The average sizes, chemical compositions and microstructure of composite particle were characterized by malvin particle size analysis instrument, Fourier transform infrared spectrometer(FT-IR), scanning electron microscope(SEM) and transmission electron microscopy(TEM), respectively. The element content of the particles surface was characterized by energy dispersive spectroscopy(EDS). The average molecular weight of polymer and the ratio of core and shell components of the composite particles were tested and characterized through gel permeation chromatography(GPC) and thermo-gravimetric analysis(TGA). And the hydrophility of the amphiphilic copolymers was tested by the contact angle tester.The results show that the morphology was influenced mainly by the St/PVDF feed ratio, the polymerization temperature, and the length of the catalyst Cu(0) wire(Φ 1.00 mm). When the feed ratio was St/PVDF = 5.0 g/1.0 g, snowman-like Janus particles were exclusively obtained. Raspberry-like and popcorn-like composite particles were observed at a higher reaction temperature or a shorter length of the catalyst wire. The reaction kinetics plots demonstrated some unique features. The formation of nonspherical composite nanoparticles can be ascribed to the surface nucleation of PS bulges following the SET-LRP. The reaction formula for the preparation of PVDF/PS-co-PDMAEMA was explored preliminarily. And the method shows a great of advantages, such as moderate and simple polymerization conditions, and clean and environmental reaction formula. It was observed that the hydrophilic property was improved compared with the macroinitiator.