United States. In nature, colors can serve as a form of communication, but they can also hide animals and plants, camouflaging them from view. Researchers have now developed polymers that can better mimic nature's color-changing capabilities than existing polymers.
In the study published by the American Chemical Society they say the materials could enable smart decorations, camouflage textiles and better anti-counterfeiting measures.
Most colors that people are familiar with, such as shades on paper, are made with pigments. But there is another type, called structural color, in which color is produced by periodically arranged microscopic structures that interfere with visible light.
For example, peacock tail feathers are brown, but the microscopic structures present in the feathers make them look blue and green to the naked eye. Scientists have used crystalline liquid cholesteric polymers (CLCs) to mimic the structural coloration found in nature because they can easily become receptive materials. But so far, researchers have only produced them in a limited range of colors. Albertus P.H.J. Schenning and Monali Moirangthem wanted to make CLC polymers with the entire visible spectrum of colors.
The team used inkjet printing technology and a calcium nitrate solution to print an image on a CLC polymer they developed. The printing of successive layers changed the degree of swelling of the CLC polymer, changing the color. One layer resulted in an orange color, a second layer changed it to green, and a third layer made it blue. As an example, the researchers used the method to draw a blue flower with green leaves on a reddish-orange background. After the ink dried, the image was no longer visible: the entire surface looked blue. However, spraying water or breathing caused the full-color image to reappear.
The Dutch Foundation for Scientific Research provided funding for the project.
Source: American Chemical Society.
