Amazon butterfly shares its secrets

Biomimetics inspired Nissan’s new vehicle fabric

By Sue Stuckey

An Amazon butterfly’s mysterious brilliant blue wings have inspired car maker Nissan’s development of a revolutionary fibre for vehicle seats and interior and exterior trim.

Like the Morpho butterfly’s wings, the fibre is not coloured but appears to be so due to a phenomenon called multi-layered thin film interference. This controls the way light is reflected and can be viewed.

The technology is based on research into biomimetics, an engineering practice that looks at prominent functions of living things and uses them in practical applications.

Scientists studying the Morpho butterfly, a native of the Amazon basin, discovered that its wings are not smooth but pleated in parallel vertical rows. Each pleat is about 0.5 Micro m wide with a similar space between the rows.

A cross-section through a pleat shows up to 10 lamella, arranged like stairs, each having a 0.08 Micro m pitch. Light reflects refractively through the lamella, producing an iridescent cobalt blue light.

Nissan’s fibre displays a high metallic sheen and a clear blue colour under exposure to different types of light including natural, fluorescent and incandescent. The colour properties and tint vary depending on the light source used and also the viewing angle.

The fibre is environmentally friendly since there is no pollution from dye waste, and it cannot cause skin rashes or allergic reaction.

Nissan is working with two other companies to develop the fibre and assess costs in full-scale production.

Teijin is responsible for the manufacturing technology and Tanaka Kikinzoku KK developed the spinneret to make it.