University of California, Riverside nanotechnologists have succeeded in controlling the color of very small particles of iron oxide suspended in water simply by applying an external magnetic field to the solution. The discovery has potential to greatly improve the quality and size of electronic display screens and to enable the manufacture of products such as erasable and rewritable electronic paper and ink that can change color electromagnetically.
When the strength of the magnetic field is changed, it alters the arrangement of the spherical iron oxide particles in solution, thereby modifying how light falling on the particles passes through or is deflected by the solution.In their experiments, the researchers found that by changing the strength of the magnetic field they were able to change the color of the iron oxide solution - similar to adjusting the color of a television screen image. They have used the superparamagnetic property of iron oxide particles to tune the spacing between nanoparticles, and therefore the wavelength of the light reflection - or the color of the colloidal crystal - by changing the strength of the external magnetic field.
Source: whatsnextnetwork.comAdded: 20 December 2007