Inspired by the small but deadly blue-ringed octopus, researchers have created a novel technology that rapidly changes color and appearance under various kinds of light, enabling camouflaging and signaling. The tech has potential applications in fields like the military, medicine, and robotics.
The greater blue-ringed octopus (Hapalochlaena lunulata) uses split-second muscle contractions to change the size and color of its titular iridescent skin patterns to camouflage itself from would-be predators and as a warning signal to other animals. The contractions stretch or compress chromatophores, small balloon-like pigment sacs in the skin.
Inspired by the cephalopod’s ability to deceive and signal, researchers from the University of California Irvine (UCI) created a technological platform that mimics it.
“We are fascinated by the mechanisms underpinning the blue-ringed octopus’ ability to rapidly switch its skin markings between hidden and exposed states,” said Alon Gorodetsky, corresponding author of the study. “For this project, we worked to mimic the octopus’ natural abilities with devices from unique materials we synthesized in our laboratory, and the result is an octopus-inspired deception and signaling system that is straightforward to fabricate, functions for a long time when operated continuously, and can even repair itself when damaged.”
The tech is very similar in construction to the rings of H. lunulata: a top transparent proton-conducting polymer electrode, a nonacene-like active layer wherein a wrinkled blue ring surrounds a flatter brown circle, an underlying acrylic membrane, and a bottom transparent proton-conducting polymer electrode. The designer nonacene-like molecules are what help give the platform some of its capabilities.
“For our devices, we conceptualized and designed a nonacene-like molecule with a unique architecture,” said Preeta Pratakshya, the study’s lead author. “Acenes are organic hydrocarbon molecules with a host of advantageous characteristics, including ease of synthesis, tunable electronic characteristics, and controllable optical properties. Our nonacene-like molecules are exceptional among acenes because they can survive years of storage in air and over a day of continuous irradiation with bright light in air. No other expanded acene displays this combined long-term stability under such harsh conditions.”
In addition to being hardy, the molecules also imbue the tech with other important blue-ring-inspired characteristics, including adjustable spectroscopic properties, straightforward benchtop fabrication using minimal equipment, and ambient-atmosphere stability under illumination.
The system consistently and reliably changed its visible appearance for around 500 cycles, with minimal to no degradation in functionality under ambient conditions. It demonstrated its capabilities in the UV-visible light-near-infrared (UV-Vis-NIR) region of the electromagnetic spectrum, including the ability to modulate visible color lightness, change near-infrared contrast, and adjust multispectral fluorescence intensity. This ability, say the researchers, would enable the tech to disguise other objects from detection or stealthily signal observers. Unexpectedly, the researchers discovered that the technology could also autonomously self-repair without user intervention.
“The photophysical robustness and general processability of our nonacene-like molecule – and presumably its variants – opens opportunities for future investigation of these compounds within the context of traditional optoelectronic systems such as light-emitting diodes and solar cells,” said Gorodetsky.
The researchers say their easy-to-manufacture technology could have applications in the military, medicine, robotics, and sustainable energy fields. And its scalability means it could be used to cover large areas such as vehicles, billboards, and even buildings.
The study was published in the journal Nature Communications, and the below video, produced by the Gorodetsky Group, compares the blue-ringed octopus’ color-changing capabilities with that of the bioinspired technology.
Source: UCI
