ADDITIVE MANUFACTURING
Is it possible to 3D-print multiple dynamic colours from a single ink? New research has proven this to be the case
HOW IT WORKS In this study, Diao and her colleagues present a UV-assisted direct-ink- write 3D-printing approach capable of altering structural colour during the printing process by tuning light to control evaporative assembly of specially designed crosslinking polymers. “Unlike traditional colours which
come from chemical pigments or dyes that absorb light, the structural colours abundant in many biological systems come from nano-textured surfaces that interfere with visible light. This makes them more vibrant and potentially more sustainable,” explains Sanghyun Jeon, lead author and a graduate student in the Diao Lab. The researchers were able to
A chameleon’s colour state at any given time is controlled by a
complex interaction of hormones, temperature, and the animal’s autonomic nervous system
I
nspired by the colour-changing ability of chameleons, researchers at a US-based university have developed a sustainable
technique to 3D-print multiple, dynamic colours from a single ink. Chameleons change colour by
dispersing or concentrating on pigment granules (melanophore cells) within the cells that contain them. In general, the animal appears lighter coloured when the pigment is concentrated and dark when the pigment is dispersed through the cells. This colour change is determined by environmental factors such as light and temperature as well as emotions. “By designing new chemistries and
printing processes, we can modulate structural colour on the fly to produce colour gradients not possible
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www.engineerlive.com An illustration of a 3D-printed chameleon courtesy of the researchers
before,” says Ying Diao, an associate professor of chemistry and chemical and biomolecular engineering at the University of Illinois Urbana- Champaign and a researcher at the Beckman Institute for Advanced Science and Technology.
produce structural colours in the visible wavelength spectrum, from deep blue to orange. And while an artist may use different paints to achieve this colour gradient, the research team used a single ink and modifies how it is printed to create the colour gradient. Co-author Charles Sing, an
associate professor of chemical and biomolecular engineering and materials science and engineering, highlights the importance of collaboration. “Only by working together could we design this system at the molecular level to yield such fascinating properties.” ●
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