The research group of ‘Physics of Interfaces and Colloidal Systems’ of the Universidad de Granada, headed by professors Fernando González Caballero and Juan de Dios García Durán, works on producing fluids with properties that change when an external magnetic field is applied, as in the case of a magnet. These are known as “intelligent fluids” and can be used in several areas, from hard industry to orthopaedic medicine and implants.
The fluids mentioned above consist of a suspension of iron particles in oil or water, modified by some special additives to improve certain characteristics. The result is a material which can flow and magnetise in a magnetic field. The fluids developed by these researchers from Granada change in viscosity when a magnetic field is applied. “The fluid flows normally without the field, but when the field is applied the viscosity can change several orders of magnitude until it becomes a rigid structure and then recovers the fluidity again when the magnetic field is removed”, explains the researcher Guillermo Iglesias, the inventor.
The main function of these fluids in the design of shoes is to cushion and adapt the pressures exerted on the sole of the foot thanks to an insole filled with this liquid. According to the researcher, the fluid is located inside cavities connected by channels, which incorporate a group of springs and magnets that contract in order to come closer or move farther away from each other. These contractions cause the opening or closing of the shut-off valve, depending on the pressure exerted by the foot. This enables a continuous and immediate adaptation at each step of the foot, because the mechanism controls the cushioning intelligently. In the words of the inventor: “if the fluid detects a vibration, it provides cushioning, if not, the cushioning is not activated”.
According to Iglesias, this cushioning system is different from other technologies which have appeared recently on the market, in the sense that it requires no electronic device and the cost of the material is low.
Versatile material
The preparation of this fluid is the key to achieve optimum performance. For this reason, the researchers have invented and patented an experimental method to characterise some fundamental properties of these materials, such as redispersion, stability, and sedimentation, studying such behaviour in a magnet field using the most advanced technologies.
These scientists have invented a product which can be used in a wide range of areas, such as: in the cushioning of vibrations, in breaks and clutches, in seismic protection of structures, in comfort systems, and in a new generation of electrical appliances.
In the area of mechanical and civil engineering, as well as in orthopaedic medicine, these fluids with special properties are starting to be applied with success.
Reference
Guillermo Iglesias Salto. Research group “Physics of Interfaces and Colloidal Systems” Department of Applied Physics of the UGR
Phone number. 958 246 309 / 655 364 610
Email address. iglesias@ugr.es
