Why Ferrofluid is revolutionary?

Ferrofluid is a type of fluid that contains suspended micro particles of iron, magnetite or cobalt in a solvent.
Interesting Engineering

Almost 60 years ago, inventor Steve Papell of NASA created a bizarre-looking liquid that could be used as rocket fuel. Called ferrofluid or magnetic fluid, the carrier fluid, usually an organic fluid such as water or kerosene, contains nanoscale ferromagnetic particles coated with a surfactant to stop them from clumping together in the liquid. These colloidal fluids would have a composition of five percent magnetic particles, 10 percent surfactant, and 85 percent carrier fluid.

The liquid becomes highly magnetized in the presence of a magnetic field. Which means you could use a magnet to move the liquid around from a distance.

How cool is that?

So, what does ferrofluid look like? It has a spiky-looking shape and resembles a bunch of razors. The odd shape is caused by the need to find a stable shape to minimize the total energy of the system - this effect is known as normal-field instability.

The particles that make up a ferrofluid have a diameter of 10 nanometers or less. This is because the particle size has to be small enough to be evenly dispersed through the liquid by the random motion of particles in a liquid due to collisions with other molecules. At the same time, they have to be large enough to contribute to the magnetic response of the fluid. 

Ferrofluids have found themselves in several applications, ranging from small electronic devices to space missions and cancer treatments.

You can also find this 'magical' liquid at your house. Due to their high thermal conductivity and heat transfer properties, they are used in devices such as loudspeakers, as the sound produced when the voice coil vibrates generates unnecessary heat. Ferrofluids help cool the voice coil.

That's not it. You can also find ferrofluids in hard drives where they seal the interior of the device. When magnetized, they form a barrier against dust and dirt that could ruin the delicate plates.

Over the years, ferrofluids also caught the interest of artists due to their visually arresting look. When artist and entrepreneur Nikola Ilic stumbled upon an online video of ferrofluid sculptures in motion created by Japanese artist Sahiko Kodama, Ilic immediately wanted a ferrofluid display for his desk.

Years later, he created a company that sells ferrofluid in glass jars for those intrigued by its movement.

The futuristic-looking liquid will have newer uses in our lifetime. Take the example of a team at the Harbin Institute of Technology in Harbin, China, where researchers published a study that demonstrated liquid microbots made from ferrofluid droplets. The droplets are oil-based as they envisage applications in the watery fluids of the body.

Evidently, ferrofluids could have a multitude of exciting possibilities in the future.