| The synthesis and application of hollow polymer microspheres is reviewed. Up to now, many techniques have been developed to fabricate polymeric hollow microspheres, such as self-assembly method, emulsion method, template-assisted polymerization and industry method. The polymeric hollow microspheres have potential applications in drug storage and controlled release, protection of biological active agents, heterogeneous catalysts and the removal of pollutant in waste water.Herein, poly[styrene-co-2-(acetoacetoxy) ethyl methacrylate-co-acrylamide] (PS-co-PAEMA-co-PAM) hollow microspheres are synthesized by template-assisted polymerization. The size of the synthesized hollow microspheres is 300 nm and the wall thickness is 50 nm. The hollow microsphere is composed of three components:1) a hydrophilic corona of PAM segment; 2) a chelate shell of PS-co-PAEMA segment; and 3) a formed hydrophobic microcavity. The unique structure of the PS-co-PAEMA-co-PAM hollow microsphere endues itself three important characters: First, the hollow microsphere can be used as scaffold, on which catalyst of Pd or Au nanoparticles is successfully immobilized. Second, the hollow microsphere can be highly dispersed in aqueous phase due to the hydrophilic segment of PAM. Third, the hollow microsphere can also act as microcapsule to encapsulate and concentrate guest organic molecules of reactants within the microcavity in aqueous solution.Due to the combined advantages of microcapsule and catalyst scaffold, the PS-co-PAEMA-co-PAM hollow microsphere with embedded Pd nanoparticles can be employed as efficient microreactor. Herein, the catalytic hydrodechlorination (HDC) of chlorophenols in the sole solvent of water and hydrogenation of olefin under organic/aqueous biphasic condition are both performed highly efficiently within the microreactor. Additionally, the microreactor is steady and the immobilized Pd nanocatalyst can be reused easily without deactivation in catalytic activity. |
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