Ferrofluid, synthesis

Ammonia fumes necessitate ferrofluid synthesis in a fume hood. Ferrofluids stain skin and clothing so lab coats and gloves are recommended. 

Gomes, J.D., Sousa, M.H., Tourinho, F.A. and Aquino, R. da Silva, G.J., Depeyrot, J., Dubois, E., Perzynski, R. (2008) Synthesis of core-shell ferrite nanopartides for ferrofluids chemical and magnetic analysis. Journal of Physical Chemistry C, 112 (16), 6220-6227. 

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. 

Kim EH, Lee HS, Kwak BK, Kim BK (2005) Synthesis of ferrofluid with magnetic nanoparticles by sonochemical method for MRI contrast agent. J Magn Magn Mater 289 328-330... 

In the third step of the synthesis route, a monomer miniemulsion with 20 wt.% dispersed phase is prepared and added to the water-based ferrofluid containing the magnetite aggregates, as obtained above. This mixture is then cosonicated, and the controlled fission/fusion process which is characteristic for miniemulsification is expected to destroy all aggregates and liquid droplets. As a consequence, only hybrid particles composed of magnetite and monomer should remain, presumably since this species shows the highest stability. Polymerization of the monomer is then started for all the samples presented here by adding an initiator. 

Fe304 nanoparticles in poly(organosilsesquioxane) with sizes of 4-15 nm were prepared by the one-pot synthesis using reverse micelle method (Ervithayasuporn et al., 2009). The ferrofluid droplets were in situ encapsulated, via pwlycondensation of molecularly self-assembled octenyltrimethoxysilane. 

E Auzans, D Zins, E Blums, R Massart. Synthesis and properties of Mn-Zn ferrite ferrofluids. J Mater Sci 1999 34 1253. 

Preparation and Properties of an Aqueous Ferrofluid Crystal Structure Intermolecular Forces Magnetism Stoichiometry Synthesis (14)... 

From Rust to High Tech Semi-Synthesis of a Ferrofluid Using FeO Nanoparticles Oxidation / Reduction Synthesis (21)... 

A typical synthesis consisted of the following degassing with Ar 0.1 g TOPO in a three-neck flask for 20 min introduction of 15 mL of anhydrous o-dichlorobenzene (DCB) -I- 0.1 mL of OA under Ar heating to reflux temperature (- 182 °C) rapid injection of 0.54 g of Co2(CO)g diluted in 3 mL of DCB (precursor solution) lowering of the temperature a few hundred seconds later and extraction of the solution. Note that to dissolve the cobalt precursor, solutions are normally vigorously shaken for 30 min. There is often a solid residue that does not go into solution, suggesting that the Co2(CO)g/DCB solution is close to saturation. Details for the reactions may be found in Table 1. This one-step reaction takes between 1 and 20 min, yielding a concentrated (10 to 10 particles per milliliter) black ferrofluid. 

Varshney S, Ohlan A, Jain VK et al (2014) Synthesis of ferrofluid based nanoarchitectured... 

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