Fe3O4 nanoparticles were prepared by chemical co-precipitation using palmitic acid as surfactant,then a uniformly dispersed system of Fe3O4@Polymethylmethacrylates(PMMA) core-shell structure was obtained.Furtherm-ore,polymethylmethacrylates(PNIPAM) was encapsulated on the surface of the Fe3O4@PMMA core-shell nano-structure to get Fe3O4@PMMA@PNIPAM double shell-core composite structure.After that,the Ag nano-particles were assembled on the surface of Fe3O4@PMMA@PNIPAM taking advantage of coordination reaction between Ag+ and nitrogen atom on the amide group of PNIPAM.The magnetism of composites is convenient for the catalyst separation from the solution.
