MNA� Iranian researchers at Amirkabir University of Technology (AUT) have developed a smart color system that changes the surface color when an outside stimulus is applied.


Naeimeh Shirkabii, the project manager, said her team has managed to develop a smart color system by using photonic crystal nanofoams.

�In terms of its chemical structure, the system uses no dyestuff,� she explained. �Their colors have a physical origin and are dependent on their structures.�

She noted that the system changes surface colors through applying an electric voltage, adding �by doing this, the refractive index of the structure changes which in turn leads to certain wavelengths of light being reflected from the system, which in turn causes the color of the structure to change.�

According to the researcher, increasing the voltage changes the blue color of the structure into red.

She maintained that the cause of color change in the system is the presence of crystal photonic nanofoams, adding �photonic crystals are a periodic�optical�nanostructure. The further the particles get from one another and with further difference in the refractive index of the structure�s components, the wavelength of the reflected light moves toward higher wavelengths and results in the various colors of the surface.�

According to Shirakbari, the color system has applications in automotive industry and military for camouflage.