Color-Shifting Material Relies on Magnetically Controlled Nanocolumns (VIDEO)
Caption
The color-changing material incorporates a regular array of micron-wide pedestals, making the polymer layer resemble a LEGO® brick. The material's middle layer is an aqueous solution containing free-floating iron oxide nanoparticles. 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. This video demonstrates a dynamic color shift from green to yellow. The video consists of three fast and one slow color change cycles when the columns are tilted from 0 to 30 degrees.
Credit
Zhiren Luo, NC State University
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