Fish-Inspired Material Changes Color Using Nanocolumns

Inspired by the flashing colors of the neon tetra fish, researchers have developed a technique for changing the color of a material by manipulating the orientation of nanostructured columns in the material.

The color-changing material has four layers. A silicon substrate is coated with a polymer that has been embedded with iron oxide nanoparticles. The polymer incorporates a regular array of micron-wide pedestals, making the polymer layer resemble a LEGO® brick. The middle layer is an aqueous solution containing free-floating iron oxide nanoparticles. This solution is held in place by a transparent polymer cover.

When a vertical magnetic field is applied beneath the substrate, it pulls the floating nanoparticles into columns, aligned over the pedestals. By changing the orientation of the magnetic field, researchers can change the orientation of the nanoparticle columns. Changing the angle of the columns shifts the wavelength of light that is most strongly reflected by the material; in practical terms, the material changes color.

Read more at North Carolina State University

Image Credit: North Carolina State University

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