Funded by the National Institutes of Health
Inert-Gas Condensation (IGC) produces highly uniform nanoclusters. For biomedical uses, clusters are dispersed into a liquid. Our laboratory uses a single-step process to fabricate magnetic nanofluids. A vapor produced by sputtering or thermal evaporation is ejected into an Ar-filled chamber. Collisions with the Ar atoms cause small, fairly monodisperse clusters to form. The clusters fall onto a rotating drum that has picked up a thin coating of a fluid and surfactant. The surfactant prevents the nanoparticles from agglomerating. The figure shows a schematic of the process. A primary advantage of this technique is that any material that can be sputtered can be made into clusters, including alloys and oxides or nitrides via reactive sputtering.
The chamber in which the materials are made is shown
to the right, along with (left to right), Ray
Lemoine, Michelle
Strand and Shaina
Remboldt, who are responsible for much of the the construction
of the apparatus.
We have made
a variety of materials, including iron, cobalt and iron-nitride magnetic fluids. The nanoparticles are transferred from the oil in
which they originally are deposited to a water-based fluid before use.