The vast ambit of bio-mimicry has previously led us to fascinating projects like – armor systems inspired by animal scales and artificial photosysnthesis aided by semiconducting nanowires. This time around, researchers at the University of Nebraska-Lincoln (UNL) looked forth to the camouflaging ability of cuttlefish, and have consequently devised an advanced material that can alter both its color and textures within a matter of seconds. This transformation is ‘fueled’ by pulses of light – which leads to the warming of the material pixels (where the light is actually absorbed). This rise in temperature in turn causes the physical morphing through diminutive ruptures on the surface of the said material.
In case of this technology, the scientists utilized a multilayered structure that was embedded with colloids – a special material that consists of tiny particles (of soda lime, glass, or copper) suspended evenly in water. The variegated layers of the structure itself comprised – a base layer with insulative property, a middle layer with light absorbing capacity, and a surface layer filled with liquid. Interestingly, when a laser light hits a surface, the color of the pixels always differs from the color of the light they are absorbing. For example, when a red light is shone on the surface, the green-hued pixels heat up and absorb the light.
To that end, when the aforementioned ruptures occur on the surface (brought on by the temperature difference of a light striking the surface), they tend to attract the colloids. As a result, these colloids move to the areas of the pixels, and then mimic the light’s true color that was incident on the surface. So, again taking the example from the last paragraph, if the original light pulse was red, the green pixels gets heated up. This induces the colloids to move to these green pixel-areas, and then mimic the color of the light exposure, which is red. In essence, the green color of the surface is transformed into red.
However, as the researchers made it clear – changing colors is not actually a new application, given the prevalence of televisions in almost every household. But where this technology truly shines pertains to its ability to also change textures with the aforementioned combination of light and heat. In that regard, the variant patterns created on the surface was achieved with differently permuted trajectories of light and the use of transparent images on the surface. In fact, one particular demonstration showcased how words and particular symbols could be ‘inscribed’ on the structure – and they would become invisible when the material cooled down, and again reappear when the material was heated.
Lastly, as for the practical application of the technology, suffice it to say the project is still in its nascent stage. However, the scientists are looking forth to a progressive scope where microscopic colloids can be used for accelerating the growth of biological tissue. Furthermore, the future might make way for a more apparent application of the system, and that entails advanced camouflage in military scenarios.