Preparation and characterization of magnetic chitosan microcapsules

By dispersing aqueous precipitant in liquid paraffin to prepare a w/o emulsion then adding chitosan (cs) solution,cs microcapsules have been successfully prepared. it is a facile way to prepare polymer microcapsules by using aqueous precipitant or nonsolvent as template,which avoids the removal of template and would free from the necessity to cross-link the microcapsule as usual methods to directly form dense shell. the hollow feature of the obtained materials is revealed. the diameter of the microcapsules ranges from several μm to over 100 μm. magnetic cs microcapsules have been prepared in this way when fe 3+ and fe 2+ were mixed with cs to prepare a mixture starting solution. the appearance and microstructure of the composite microcapsules were studied. the results indicate that the formed fe 3o 4 nanoparticles are embedded in the cs matrix evenly due to strong interaction between the fe 3o 4 nanoparticles and the cs molecules. the fe 3o 4 content and the magnetic properties of the composite microcapsule were measured. the composite microcapsules were calcined in air at 700°c to prepare pure inorganic hollow microspheres. it is general to prepare hollow polymeric or composite particles by using this method. © 2013 xiaopeng xiong et al.