Nanotechnology - Is it useful?

Do we have any use of Nanotechnology in the field of ferrofluids?

hi nanotechnology is the present emerging technolg . nano sensors and anano bio sensors are making revolution inthe present life

Yes. Nanotechnology is definitely useful in this area.
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A ferrofluid is a liquid which becomes strongly polarised in the presence of a magnetic field. Ferrofluids are composed of nanoscale ferromagnetic particles suspended in a carrier fluid, usually an organic solvent or water. The ferromagnetic nano-particles are coated with a surfactant to prevent their agglomeration (due to van der Waals and magnetic forces). Although the name suggests otherwise, ferrofluids do not display ferromagnetism, since they do not retain magnetisation in the absence of an externally-applied field. In fact, ferrofluids display paramagnetism, and are often referred as being "superparamagnetic" due to their large magnetic susceptibility. Although current theory does not preclude the possibility of a truly ferromagnetic fluid, no such fluid has yet been observed.

Thank you but I saw that earlier. There is a word nanoscale ferromagnetic particles in that definition but its not making sense to me as to how nanotechnology is aiding in it...

Nanotechnology is aiding the particles to be at nano dimensions. If developements in nanotechnology were not there, it would have been just ferromagnetic particles instead of " nanoscale ferromagnetic particles". the word originated because of the advanced made in the field of nanotechnology only. does that satisfy you?

Added after 7 minutes:

In simple words, ferrofluids are an application of nanotechnology.
Due to the progress of nanotechnology only they came into existance. so there is no point of nanotechnology being useful in ferrofluids, since it is the basis for it.

Thank you so much Sir. That clarifies my doubt.