A group at The University of Bristol have come up with the world's first magnetic soap. At first, this sounds like just another interesting technological leap from soap on a rope — plus a way to combine two of the world's coolest things, soap and magnets. But actually, this invention could have a much more vital purpose.
Many people recall the BP oil spill that wrought havok on the Gulf of Mexico recently. One of the strategies used to clean up the spill was sending a bunch of soap-like molecules after the oil. The soap breaks up the oil on the ocean, much like it does on dishes in the sink. The oils slicks that float across the top of the ocean, coating everything in their path, are dissolved into patches clustered with soap molecules, which sink to the bottom of the ocean. There it stays, while bacteria feast on it and convert the harmful chemicals to another link in the food chain.
But environmentalists are not always fans of this solution. This is partly because the oil that drops can stay on the ocean floor for thousands of years, and can be washed up on shore, long after environmental clean-up efforts have moved on. A more immediate concern is the fact that soap isn't really much better for ocean habitats than oil is. If only the soap could be contained — or easily re-collected, after it was sent in the ocean.
Hence the creation of magnetic soap. Here's how it works.
Soaps are known as surfactants, because they lower surface tension, letting liquids surround particles, break them up, more completely and washing them away. Some surfactants have ions dissolved in them, like bromide and chloride. Ions have a net charge, making them attract metal atoms. When scientists added tiny bits of iron to the solution, the ions clumped around them, creating groups of soap molecules with metal centers. The team put these new solutions inside test tubes and poured a liquid that did not mix with the soap on top of the solutions. When they lowered a magnet into the middle of the top liquid, the soap solution defied gravity, flying up through the lighter liquid to cluster around the magnet.
So too can soap in the ocean, dumped in to help break up and sink a spill, rise up and cluster around a magnet, letting it be re-collected quickly and efficiently, without doing more damage. They might also be able to use magnets to target a spill directly, drawing the surfactant to where the spill is, and using less chemicals over all. But spills aren't the only use for magnetic soap. Surfactants, which are used in all kinds of industrial applications, take on the properties of metal. They can conduct electricity, be turned on and off by application of an electric current, and can change shape via different applications of charge.
Image: Frank Eugene Austin
Bar Magnet Image: Alexander Wilmer Duff