Synthesis and Characterization of SiO_2-Coated P(St-4VP) Nanocomposite Particles

The poly(styrene-co-4-vinylpyridine)(P(St-4VP)) particles were first synthesized by using 4- vinylpyridine(4VP) as the functional comonomer.The SiO_2 nanoparticles were subsequently coated on the P(St- 4VP) particles through the sol-gel nano-coating process in the NH_4OH/ethanol medium.Finally,the SiO_2-coated P (St-4VP)(P(St-4VP)/SiO_2) nanocomposite particles were prepared.The roughness of the SiO_2 shell of the nanocomposite particles increased with increasing the 4VP content in the P(St-4VP) copolymer.With increasing the polyvinylpyrrolidone(PVP) content,the amounts of the P(St-4VP) particles increased,and thus the size of the nanocomposite particles decreased,and synchronously the smoothness of the SiO_2 shell increased.The roughness of the SiO_2 shell of the nanocomposite particles increased with increasing the content of NH_4OH and tetraethoxysilane (TEOS).On the other hand,the thickness of the SiO_2 shell increased with increasing the TEOS content.