Engineering conjures up futuristic cars and gravity defying bridges. But its more subtle aspects are not always appreciated. One nuanced facet of engineering is COLOR. “Colors are an often untapped gateway into the human subconscious and can be used to give context, add awareness, and illicit specific emotions to systems,” explains software engineer Jayden Pareira in an article about what his engineering degree didn’t teach him.
Like all sciences, color engineering has gotten more sophisticated as materials with unique visual properties are brought to the field. In plasmonic color engineering, miniscule metal nanoparticles are harnessed to absorb and scatter light in ways that generate unique colors. The hues can be fine-tuned by varying the shape and size of the nanoparticles and create bichromic effects — where the color looks different depending on angle of viewing.
It's easy to accept the importance of color in design but color engineering is not just for visual effects. A new class of inks can control temperature through their structural effects.
A recent paper explains how the amount of radiation passing through them varies, enabling heating or cooling. In a nutshell, the inks transform in response to temperature. “The potential of this material is huge as it can be used for so many different purposes — like preventing heat build-up in laptop electronics or on car windshields. But the beauty of this material is that we can adjust its heat absorption properties to suit our needs,” says study author Mohammad Taha.
Color-shifting dyes have already made a splash. Materials scientists just made prototype wearable colorimetric UV sensors for sun protection. The accessories contain photo-switches that warn people when they’ve had too much sun exposure by changing from colorless to pink.
Even better, they can be reset and therefore reused. And, according to the study author Nathan Boase, “They are unpowered and do not require digital technology to function, but there is potential to integrate with smart phone technology for tracking exposure."
A new study discovered an unexpected electron structure in dyes which absorb near-infrared wavelengths of light (just beyond visible). Near-infrared dyes already had myriad applications, from filters in smartphone cameras to protective car windshields, but their molecular configuration wasn’t understood.
It turns out they range from closed shell to intermediate to open shell (how their electrons are arranged), which bodes new uses. Says study author Takeshi Maeda, “We hope that this will lead to…the development of new near-infrared absorbing organic materials that be used in society.”
Regardless, other animals are already deep into their own magic with near-infrared wavelengths of light. Australian birds, such as the orange chat, keep their body temperature from getting too high by reflecting away near-infrared sunlight. Barbed feathers on their backs and heads structurally confer high reflectivity. Birds in hotter habitats reflect more near-infrared light than birds in cooler habitats; and smaller birds that could overheat more quickly have more reflectivity than larger birds.
So, while we continue to toil away at color engineering, go birds!