Ferrofluids procedure

Since most of magnetic materials are metal or metal oxides, the raw material is straightforward and can be easily found. However, the technology difficulties remain in the purity section. As mentioned above, the different chemical properties are based on the structure and the concentration of the alloys, so the synthesis process has to be controlled very carefiilly. Furthermore, when it comes to the nanoscale, many of the classic physics laws are not applicable and quantum physics is required. The synthesis of ferrofluid consists of synthetic procedures. Basically, it is the thermal decomposition of metal organic compounds or the thermal decomposition of monometallic metal organic compounds. Figure 1.1 shows examples of magnetic nanoparticles for one simple structure and for metal alloy compounds. 

To confirm the stability of ferrofluid against dilution, freeze-thaw cycles and magnetic heating, DLS measurements on samples of diverse magnetite content were executed prior to and after the respective procedures. The results are shown in Table 1 and confirm in all cases the excellent dispersion stability of the investigated samples, with hydrodynamic diameters dh between 17 nm and 21 nm in all cases. This finding is an important sign for the reversibility of our experiments. 

An important feature of this procedure is that addition of the enzyme to the reaction mixture during the formation of the gel minimizes enzyme deactivation. Furthermore, covalent incorporation of the enzyme into the gel provides some protection against proteases. Second, the procedure is simple and of general use and should be directly applicable to a variety of enzyme systems as well as immobilization of whole cells and organelles. Finally, the gel can be rendered susceptible to magnetic filtration by including a ferrofluid in the gel formation step. 

During the 2007-2008 acaderttic year, we intend to pilot a ferrofluid lab in several sections of the first semester general cherrristry laboratory 30). The procedure will be rewritten to emphasize stoichiometric concepts inclnding limiting reagent and yield. Eventnally, we anticipate nsing this lab in all first semester sectiorrs and the modified version of the Color My Nanoworld (77) in all second semester sections. 

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