Scientists from the University of Bristol have developed a new kind of soap, composed of iron-rich salts that were dissolved in water, that responds to magnetic fields when placed in a solution. The soap’s magnetic properties were demonstrated at the Institut Laue-Langevin and were caused by tiny, iron-rich clumps that sit in the watery solution. This functional soap could revolutionize the clean-ups of oil spills.
Researchers have been looking for ways to control surfactants once they are in solution, in order to increase their ability to dissolve oils and remove them. The team had previously worked with soaps that were sensitive to light, carbon dioxide, changes in pH, temperature or pressure. This last breakthrough was reported in Angewandte Chemie and is the world’s first magnetic soap.
Ionic liquid surfactants have been suggested to be potentially controllable by magnets for some time, but scientists had assumed that their metallic centers, iron bound to halides such as bromine or chlorine, would prevent the long-range interactions required of them.
The team lead by Professor Julian Eastoe produced their variant of magnetic soap by dissolving inert surfactant materials, similar to those found in mouthwash or fabric softener. The soap has been able to overcome both gravity and surface tension. Once they developed the surfactant, they took it to the Institut Laue-Langevin, the flagship center for neutron science thanks to the world’s most intense neutron source.
There are many applications for magnetic soaps in industrial settings, but one of the most interesting is that they might be able to help clean up oil spills.
Reference: “Magnetic Control over Liquid Surface Properties with Responsive Surfactants” by Paul Brown, Alexey Bushmelev, Dr. Craig P. Butts, Dr. Jing Cheng, Prof. Julian Eastoe, Dr. Isabelle Grillo, Dr. Richard K. Heenan and Prof. Annette M. Schmidt, 20 January 2012, Angewandte Chemie.