New Scientist - Harness viruses to make dazzling colours without dye
Talk about a viral idea. Vibrant reds, blues, greens and yellows have been made without any dye or paint. Instead the colours arise from an intricate pattern of virus particles that reflects only certain wavelengths of light.
Films made at high virus concentration and slow pulling speed were iridescent, meaning the colour depended on the viewing angle, while tugging at higher speeds compressed the wiggles in the noodles, creating films with uniform colour. Stripes of different colour were made on the same slide by varying the precise speed, resulting in red, blue, green and yellow stripes.
The ability to produce many different films from a single building block is a good way to make an inexpensive coating, says Amy Blum of Ï㽶ÊÓƵ in Montreal, Canada. She also suggests using viruses to create bleach-resistant colour in clothing. Bleaching occurs when the chemical bonds of a pigment that absorb light of a certain frequency are modified so that they no longer do so. Since these coatings create colour in a completely different way, they may not be susceptible to bleaching.