Preparation Of Hollow Polymer Microspheres With Hydrophilic/Hydrophobic Asymmetric Surface And Loading Of Nano-Particles

As a micro-reactor, hollow microspheres with microporous could be used to load magnetic particles or Ag, Au and other metal nanoparticles, preparing composite particles, which have the function of both hollow spheres and nanoparticles. Such composite particles have application in the biomedical,biomimetic materials, catalyst, optical materials and other areas.In this thesis, four parts research including:prepare asymmetric hollow polymer microspheres;load Fe3O4 magnetic particles in hollow microspheres; load Au nanoparticles in hollow microspheres; prepare Ag nanoparticles outside the hollow microspheres.Hollow polymer microspheres with micropores of 14.9 nm, alkyl bromine groups on exterior wall and carboxyl groups on interior wall were produced through three steps:a) synthesis of the core-shell microparticles with copolymer of maleic anhydride (MAn) and divinyl benzene (DVB) as the core, and copolymer of maleic anhydride (MAn) and vinylacetate (VAc)as the shell;b)surface bromizing of the core-shell microparticles; c) etching of the cores with acetone, and followed by the hydrolyzing of the anhydride groups on interior wall.Using the resultant hollow polymer microsphere as micro-reactors, Fe3O4 magnetic particles were loaded into the cavity by selective adsorption of Fe2+ and Fe3+ on the interior wall, and coprecipitation only inside the hollow polymer microspheres. In addition, influences of parameters relating to the above mentioned reaction, such as the mole ratio of Fe2+ and Fe3+,reaction temperature and reaction time, on the saturation magnetization of the magnetic hollow microspheres were investigated. The results showed that the optimum reaction condition to balance the loading selectivity and value of saturation magnetization was as follows:a Fe2+ to Fe3+ molar ratio of 2/3,reaction temperature is 80℃and reaction time is 1 h.Under appropriate experimental conditions, single gold nanoparticles could be loaded in hollow polymeric microspheres. By increasing the amount of HAuCl4 and loading twice, bigger nano-particle could be obtained.In addition, polymer microspheres coated silver nanoparticles were prepared used the hollow particles as carrier. By amino-modified, the interaction between hollow microspheres and water/Ag+ were improved, to a better coating of silver nanoparticles on hollow microspheres.