The new research into the ‘smart material’ comes from the University of Luxembourg. Here the liquid crystal shells are being discussed as an enabling material, and trials are already underway for a new type of sensor.
Liquid crystals are not new technology (they are found in flat screen television sets, for example); what is new is what is being discovered in terms of how the crystals can be controlled and manipulated. The crystals possess special mechanical and optical properties at the microscopic level.
The shells are tiny, just portions of a millimeter in size. This property allows the crystals to be readily applied to a variety of surfaces. Once on a surface, the crystals can be used to selectively reflect light. The shells can be fabricated to reflect light of certain wavelengths, or ‘omidirectionally’ as the researchers describe it. This can be undertaken with specific polarization and wavelength, tunable from the ultraviolet to the infrared range. This allows anyone viewing at a display created using the crystals to see the same image from any position, even when the image is moving at any speed.
They can also be put into different patterns, to create codes that can be scanned, read and interpreted by machines.
It is this latter property that has a potential automobile application, according to Professor Jan Lagerwall, who leads the research team at the University of Luxembourg. He tells Controlled Environments magazine: “These patterns could be used to guide autonomous vehicles or to instruct robots when handling workpieces in a factory. This could become important especially in indoors applications where GPS devices don’t work.”
Such codes also mean that the liquid crystals could be coated onto objects of high value subject to counterfeiting, allowing stolen good to be scanned and the owner to be identified.
A further application, and one under investigation, is as sensors. Here the crystal shells can be deployed as pressure sensors fitted into the fingertips of robots. This helps to enable tactile feeling into machines, which is something that is currently difficult to achieve in robotic engineering
The latest research into the liquid crystals has been published in the journal Advanced Materials. The paper is titled “Cholesteric Liquid Crystal Shells as Enabling Material for Information‐Rich Design and Architecture.”
