FerrofluidThe Concepts of FerrofluidSebastian RomeroScienceMrs. Reid17 November 2017 All magnets are solid, except ferrofluid, which is a liquid. That is what makes it different. Ferrofluid was developed by NASA’s Steve Papell in 1963 to manipulate fuel in space. What was needed was an easily movable fuel that would be controlled by a supermagnet. This paper will explore what ferrofluid is made of, how surfactants work, and how magnetism works.Ferrofluid is about, ” 5% magnetic solids, 10% surfactant and 85% carrier, by volume” (MAG par 3). It also needs a ” stable colloidal suspension which is of superparamagnetic iron oxide nanoparticles ” (Hussaini par 4). Because of their small size, the particles turn ferrimagnetic, a weak form of a permanent magnet is a Ferromagnet, magnetite into a superparamagnetic (When a particle is a certain size, and have a specific magnetic domain) (Oxford dictionary) material. Ferromagnetism is the type of magnetism used in permanent magnets. Small magnetic particles would normally connect and stay together, however, due to the increased surface area in the liquid, this tendency is negated and the magnetite is not allowed to bunch up and lose its innate properties. Once the surfactant is bonded to the nanoparticle, it is considered a ligand (Lucas). In addition, researchers have also used ferromagnetic compounds such as, “Cobalt, Iron, manganese, zinc, and ferrite” to produce ferrofluids (Hussaini par 3). Most research done today has been on the ferrofluids containing magnetite The most commonly used ferrofluid is an oil-based carrier fluid with magnetite as the magnet, and it uses the magnetic push and pull, and Oleic acid as the surfactant (MAG). Ferrofluid operate quite differently than common liquids when they interact with a magnet, since they are composed of 5% ferromagnetic particles. When this solution is brought into the presence of a magnetic field, the ferromagnetic fluid experiences force along the magnetic field lines and acts by getting pulled by the field (Monet). But there is another force at play other than the magnetic field. This force is named surface tension. Consequently, the ferrofluid assumes the lowest possible surface area. That way, fewer molecules are in the high energy region. In order for Ferrofluids to push or pull to another magnet, two things need to happen. The iron particles require to be small, in order that their displacements are in synchrony with other particles in the magnetic field. Once the particles are small enough to get to the nanoscale, “(between 1 and 100 nanometers)” (Monet par 3), they react with one another in tandem with the magnetic field. In order to create ferrofluid, the nanoparticles must be coated with a surfactant. Nanoparticles must be coated with a surfactant to constitute a ferrofluid. The surfactant is what keeps all the Magnetite in place, so it doesn’t leave the ferrofluid. This is why whenever Ferrofluid is subjected to a magnetic field, it spikes up. However, the surfactant tends to break down over time (a few years), and eventually the nanoparticles in the ferrofluid will accumulate into a mass, and they will separate out and no longer contribute to the fluid’s magnetic response. A surfactant must be compatible with the carrier and should be able to overcome attractive forces like Van Der Val’s force and the magnetic force between the particles (Lucas par 4). Surfactants are also responsible for prolonging the settling rate in ferrofluids, but they also reduce the fluid’s magnetic properties (specifically, the fluid’s magnetic pull and push).The ferrofluid has very small particles (on the nano-scale) of a ferrite salt suspended in a solvent such as water. Each particle, however small, has been coated with a surfactant before being introduced to the solvent. The main purpose of using a surfactant is to allow the Magnetite to easily spread through the liquid. This ensures that the particles are not too clumped and stuck together inside the solvent. The surfactant is also used to lower the surface tension between any two liquids or between a liquid and a solid (Hussanie 6). The common surfactants used in ferrofluids are,” oleic acid, tetramethylammonium hydroxide, citric acid, and soy lecithin” (Apex par 3), but these are not the only ones that can be used. That is why when ferrofluid comes in contact with metal its spikes are not reduced to a stub, but are edged. Magnetism is what makes Ferrofluid spike up, but how does magnetism work. Magnetism is one aspect of the combined electromagnetic force that moves the ferrofluid when it is in the area of a magnet’s magnetic pull. In the magnetic field, it exerts force on the particles and aligns them to form the spike shape. Magnetism is the physical phenomena from the force caused by magnets, objects that produce fields that attract or repel other objects, but in the case of Ferrofluid, it is always attracted to the magnet. Rotating electric charges generate the magnetic fields. Most electrons tend to form pairs in which one of them is “spin up” and the other is “spin down,” in accordance with the Pauli Exclusion Principle. This principle states that two electrons cannot occupy the same energy state at the same time. In most cases, their magnetic fields are in opposite directions, so they cancel each other. However, some atoms contain one or more unpaired electrons, whose spin produce a directional magnetic field. Whichever direction the spin goes is the magnetic direction of the magnetic field. If the alignment of unpaired electrons persists without the addition of an external magnetic field or electric current, it produces a permanent magnet. It should be noted that in magnetic metals, magnetism comes purely from the alignment of forces exerted by electrons as they spin on their axes, whereas the forces created by their orbital motion around the nucleus tend to cancel one another out, but in magnetic rare earth elements such as cerium, comes both from rotational and orbital forms of motion(Lucas). Ferromagnetism is the process by which a magnet becomes permanent (Lucas). Ferrofluid is not a permanent magnet. Indeed, its magnetism is lost immediately upon being removed from the range of the magnetic field (Mag 3). Ferrofluid is used in many ways. For example, Chris Suprock, an engineer from Suprock Technologies, recently developed a device thatuses ferrofluid to mimic the heart’s ability to pump blood. Suprock’s team is working on a prototype that will combine several of these devices to make an artificial human heart thatdoesn’t rely on motors or mechanical parts. The artificial heart has an elastic membrane uses an electromagnet to stretch and contract the ferrofluid (Nicklsburg par 2)There are many additional medical uses for ferrofluid. Some include using Ferrofluids to direct drugs to localized areas to treat cancerous cells and tumors, without subjecting the entire body to the strong chemicals used in chemotherapy (Nickelsburg par 4). Ferrofluid can behave as a liquid O ring as well and has applications for X-rays. When it is applied to the X-ray, a rotating shaft enters a chamber. The Ferrofluid is positioned by permanent magnets to form a tight seal which eliminates friction. This is called high a performance shaft seal. The rotating shaft seals are used in rotating X-ray anode generators,” which lets electrons accelerate,” (X-ray) and in vacuum generators in the semiconductor industry. Ferrofluids can also be used in eye surgery. In the future, ferrofluids may be used to transmit medicines to different body parts by magnetic field application. Research is also being done concerning using them as the contrast for Magnetic Resonance Imaging. Doctors are also working on a way to eliminate tumors by injecting them with ferrofluids and then activating the ferrofluid with a magnetic field (Nickelsburg). However, not all of the uses are for medicine. Like the semiconductor industry, which uses ferrofluid to create airtight seals around rotating shafts for low-pressure tools that process the silicon pieces that form computer chips. NASA has also experimented with flowing ferrofluids in a closed loop with electromagnets as an altitude control system, and NASA is also looking at applications for zero-gravity fuel systems. Other companies are also looking into navigation systems, vibration dampening, and medical delivery systems. Using ferrofluids they have also been used to enable audio speakers to function more efficiently, with improved audio. Ferrofluids can be used to improve performance in applications that include inclinometers, accelerometers and flow meters, tilt, vibration, pressure and level sensors, and various switches (Ferrotech). Ferrofluid is used in many applications through its changes in shape and properties. Everything from its magnetism that pulls it to other objects, what it’s used for, how it works, what’s inside it, and even to its surfactants that don’t let the magnetite clump together is fascinating. But my research has brought me to a question. How do changes in the magnetic field, change the shape and properties of a ferrofluid? Work Cited “Ferrimagnetic.” Dictionary.com, Dictionary.com, www.dictionary.com/browse/ferrimagnetic.Ferrofluid, Ferrotec, ferrofluid.ferrotec.comFerrofluid, Ferrotech, ferrofluid.ferrotec.com/applications/. Hussaini, Umair. “Ferrofluid – It’s shiny, metallic and ridiculously fun to watch in action . TECHNOBYTE, TECHNOBYTE, 20 Sept. 2017, https://www.technobyte.org/interesting-facts/ferrofluid-shiny-metallic/ Lucas, Jim. “What is magnetism.” Live Science, Jim Lucas, 28 July 2015,         www.livescience.com/38059-magnetism.html  . Mag, HS. “20 Awesome Ferrofluid Facts.” Magnets By HSMAG, HSMAG, 28 July 2016,                       www.hsmagnets.com/blog/20-ferrofluid-awesome-facts/.Monet, John. “Ferrofluid fun facts.” Particles Matter, John Monet, 27 June 2013, particlesmatter.org/2013/06/ferrofluid-fun-and-facts/. Nicklesburg, Monica. “This incredible magnetic fluid may be the future of biotechnology.” The Week, The Week, This incredible magnetic fluid may be the future of biotechnology.http://theweek.com/articles/450377/incredible-magnetic-fluid-may-future-biotechnology “Superparamagnetism | Definition of superparamagnetism in English by Oxford Dictionaries.” Oxford Dictionaries | English, Oxford Dictionaries, en.oxforddictionaries.com/definition/superparamagnetism.”The Science Behind Ferrofluids.” Apex Magnets, www.apexmagnets.com/news-how-tos/the-science-behind-ferrofluids/. X-Ray Generators, NDE, www.nde-ed.org/EducationResources/HighSchool/Radiography/xraygenerators.htm.