Adapted from: https://www.deccanherald.com/science/nanotech-for-next-gen-colours-1180991.html
In recent times, there has been a growing utilization of nanostructures in industrial procedures aimed at replicating natural hues via synthetic means. These nanostructures are employed to manipulate light, creating artificial structural colors that draw inspiration from natural color schemes. The intricate and high-end nature of these techniques, coupled with their associated carbon footprint, has prompted certain sectors of the industry to seek more resilient and economical substitutes.
Scientists at the Indian Institute of Science (IISc) are actively involved in a sustainability-oriented approach. They are currently focusing on developing an affordable, one-step manufacturing method for creating reflective displays and mechanochromic sensors. This initiative is taking place at the Laboratory of Advanced Nanostructures for Photonics and Electronics (LANSPE), within the Department of Instrumentation and Applied Physics (IAP) at IISc.
Mechanochromism is the term used to describe the alteration of a material’s color when subjected to mechanical strain. The team of researchers is currently exploring a novel fabrication technique that enables the medium of display to be dynamically adjustable. This technique represents a notable advancement over current methods, which typically involve intricate, multi-phase manufacturing processes. Notably, this new technique shows potential for scalability and a wide array of applications, including implementation in soft robotics, pressure sensors, and intelligent window systems.
A range of Colors
At LANSPE, Tapajyoti Das Gupta and his team work with samples made of a special stuff called polydimethylsiloxane (PDMS). It’s kind of like noodles with different amounts of gravy, and they can control how much gravy they use. This gravy-like stuff interacts with Liquid Gallium metal to make these cool layered droplets. The team has been studying how this gravy and Liquid Gallium get along.
Das Gupta emphasizes that the amount of liquid in the sample is crucial because it determines the wide range of colors they can create, covering almost the entire color spectrum. The research team experiments with the characteristics of PDMS to create optical gadgets that can change their appearance. “By adjusting these PDMS properties, we can significantly change the size of the particles, and the corresponding color that will be rendered, something that hasn’t been achieved before,” he explains.
Through careful adjustments to the strain effect, the researchers have successfully altered the color, brightness, and CIE (a system that measures and defines how humans see color). In the lab, the team demonstrates how they put the technology through rigorous testing to ensure its durability. They analyze and reproduce the color changes in the sample over “more than a thousand cycles” to confirm its reliability.
Das Gupta suggests that this technology has the capacity to revolutionize the creation and production of high-color displays, including advertising setups. The aim was to find more affordable, straightforward, and easily expandable manufacturing methods.
According to Das Gupta, this method involves a simple and cost-effective process. With just a deposition of a few hundred nanometers of film, it can produce a range of colors. While LED displays are known for their high energy consumption, the fabrication method employed in this process ensures that the system can function effectively even in the presence of some ambient light.