The Secret Lives of Soaps
Soaps are molecules in the throes of an identity crisis -- namely, a love-hate relationship with water. One part of the molecule, the ionic hydrophilic end, longs for water's clean embrace; but the other side -- the unseemly, scandalously organic hydrophobic end -- feels more at home with a filthier element. Word on the street is, it shamelessly bonds with grease, oil and dirt.
When you squirt dish soap into greasy water, surfactant molecules surround the droplets of grease, with the water-loving ends facing outward in a kind of reverse huddle while the water-hating ends face inward in a rugby scrum.
Left to its own devices, grease would clump up with its oily friends, undergo a falling out with water and redeposit. Water, preferring its own kind to this unsavory element, would help by pushing it out via surface tension. Soaps, by grabbing gunk in a molecular bear hug, prevent this from happening so that water can wash the dirt away.
In principle, magnetic soap sounds like a simple idea: You just take some detergent and mix in some magnetic metals, right? Well, not so fast. Until recently, scientists thought that such metal ions would end up isolated in the mixture. Since individual ions aren't magnetic, this would render their contribution moot [source: Danigelis].
But then the Bristol researchers discovered something interesting: As they added their iron-containing surfactants to the solution, the minuscule clumps organized, creating an iron core that magnetic fields could get a grip on [sources: Hadlington; University of Bristol]. Eastoe and his team made the switch using iron salts that contained bromine and chlorine ions, like those found in mouthwash and fabric softener [sources: Drury; Roach; Brown].
Lab tests reveal that the magnetized soaps remove soil just as effectively as unmagnetized ones [source: Eastoe]. The researchers also found that magnet fields could change the soap's electrical conductivity and melting point. Usually, science and industry manipulate these aspects by adding an electrical charge to the soap, or by altering the system's pH, temperature or pressure [sources: Danigelis; Roach; Solon].
Because the magnetic soap consists of common chemicals, it makes an attractive and cheap candidate for scaling up -- which could speed its journey from the lab to industry, perhaps in the form of water-treatment or industrial-cleaning products [source: Flatow; Solon]. One day, it might even make it into the home.
Eastoe and his team are already looking beyond their iron salts toward potentially more promising ionic replacements. They have begun applying the technique to biological macromolecules, amino acids and proteins [source: Eastoe]. Several industry groups, including pharmaceutical companies, have expressed interest in the magnetic surfactants as well [sources: Drury; Eastoe].
Now that the results have been published, and magnetic soaps are in the hands of the broader scientific community, who knows what innovations might bubble up?