Preparation, Characterization And Application Of Metal Oxide Nanoparticles With Spherical Polyelectrolyte Brush

In recent years, metal oxide nanomaterials have received much attention due to their unique chemical and physical characteristics. Metal oxide nanomaterials exhibit excellent catalytic performance because of their high surface-to-volume ratio, which lead to an excellent potential in application of water treatment. However, the nano-sized particles tend to aggregate due to specific surface energy. Until now, synthesis of stable nano-sized metal oxide particles with small sizes and a narrow size distribution presents still a challenge.Here we present that spherical polyelectrolyte brushes (SPB) particles can serve as well-defined nanor-reactors for synthesis of zinc oxide nanoparticles and magnetic nanoparticles. We synthesized two different SPBs through two different method-photo-initially emulsion polymerization and thermal-initially emulsion polymerization. In addition, we also studied the photo-catalytic ability of zinc oxide nanoparticles. Our main work includes:(1) PB-PAA SPBs were synthesized via thermal-initially emulsion polymerization. The PB-PAA SPBs consist of a core of poly (butadiene) latex and a shell of linear poly (acrylic acid) grafted on PB core. Then the SPBs acted as a nanoreactor and a carrier, which attracted and synthesized zinc oxide nanoparticles inside. The average diameter of these zinc oxide nanoparticles were about20nm, also, the existence of the long PAA chains also prevent aggregation and sedimentation. Besides, becau under UV irradiation, zinc oxide nanoparticles can oxidize organic pollutants in water into water, dioxide and others. Here we evaluated its photocatalytic activity by measuring the degradation of methyl orange(2)PS-PAA SPBs were synthesized via photo-initially emulsion polymerization. These PS-PAA SPBs consist of a core of poly (acrylic acid) latex and a shell of linear poly (acrylic acid) grafted on PS core. The HMEM was used as photo-initiator. With the UV initiation, PAA chains were grafted to PS particles. After that, we also synthesized zinc oxide nanoparticles inside. Then we compared the differences between these two zinc oxide nanomaterials which were synthesized through two different ways. It was found that the dispersity and photocatalytic ability of ZnO particles from PS-PAA were not as good as the other. The reasons were studied.(3)Magnetic nanoparticles were synthesized within the SPBs carriers. The average diameter of these magnetic nanoparticles were about10mm, which was smaller than the as-prepared zinc oxide nanoparticles. In order to increase its magnetic content, we applied a "multi-synthesis method". It was proved with experiment that the best number of "multi-times" was six. And the magnetic content could achieve11wt.%.