There are some differences between conventional automobiles and autonomous vehicle prototypes and concepts that are blindingly obvious – no steering wheel, multi-use glass panels, rear-facing front seats, for example. But look closer and it is clear that AV manufacturers have grabbed the opportunity to rip up the automotive rule book with both hands for the new generation of transportation.

An example of future possibilities for different materials to be used in AVs has been revealed by scientists from the University of Luxembourg, whose research has shown the potential for liquid crystal shells – as seen in flat screen TVs, for example – to be used as an enabling material. Professor Jan Lagerwall, from the physics and materials science research unit (PHYMS) at the University has been investigating, along with his team, the mechanical and optical properties of microscopic shells made of liquid crystal for several years. Now, in a multidisciplinary collaboration with IT scientists, members of the University's Interdisciplinary Center for Security and Trust (SnT), and an assistant professor at the New Jersey Institute of Technology, have published a report describing potentially groundbreaking future applications for the material.

Liquid crystal shells, only fractions of a millimeter in size, can easily be applied to surfaces, and have several unique properties that could be applied in engineering. As they reflect light highly selectively, they can be arranged into patterns that are readable for machines, akin to a QR code, adding coded information to objects. "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," Prof Lagerwall explains.

The shells can be manufactured to reflect only certain wavelengths of light, such as infrared, that would be invisible to the human eye. As the liquid crystal shells reflect light "omnidirectionally," (the same pattern is seen, regardless of their position and viewing angle) the patterns can even be read by moving objects. Additionally, the shells can be manufactured using a method that means they change their structure when exposed to certain external impacts, such as pressure, heat or specific chemicals.

 

Common senses

Elsewhere, two other US universities are also working on materials for AV sensing technologies. Detecting and sensing objects is paramount with AVs and hurdles such as fog or bad weather should not detract from the aim of a sense of surroundings. Compared to the current visible light-based cameras, infrared cameras can offer much better visibility through the fog, smoke or tiny particles that can scatter the visible light.

Within the air, infrared light – within a specific range called mid-wave infrared – scatters much less compared to other visible or other infrared light waves. Infrared cameras can also see more effectively in the dark, when there is no visible light. However, the high costs of infrared cameras is a hinderance to their deployment in vehicles, but a material developed by scientists at the USC Viterbi School of Engineering and the University of Wisconsin might show promise for such infrared detection applications as autonomous vehicles, emergency services and even manufacturing.

The research group of Jayakanth Ravichandran, an assistant professor of materials sciences at the USC Viterbi School of Engineering has been studying a new class of materials called chalcogenide perovskites. Among these materials is Barium titanium sulfide (BTS), which researchers discovered interacted differently with light in two different directions. "This is a significant breakthrough, which can affect many infrared applications," says Ravichandran.

This direction dependent interaction with light is characterized by an optical property called birefringence. In simple terms, birefringence can be viewed as light moving at different speeds in two directions in a material. The BTS material can be used to construct a sensor to filter out certain polarizations of light to achieve better contrast of the image. It could also help filter light coming from different directions to enable sensing of a remote object's features. This could be particularly important for improving infrared vision used in autonomous vehicles, which need to see the entire landscape around them even in low visibility conditions.

"The hope is that in the future, a BTS-enhanced sensor in a car would function as retinas do to the human body," says Shanyuan Niu, a doctoral candidate in the Materials Science program at USC.

 

Evolution, not revolution

Inside the vehicle, many of the materials will stay the same – albeit with some upgrades, especially the likes of plastic and rubber. Eugenio Toccalino, DuPont's global director for automotive, says new opportunities for these commonly used materials include electromagnetic shielding; noise, antivibration and harshness applications; and thermal management.

To find the right solutions, the likes of DuPont and Freudenberg-NOK are looking outside the automotive sphere, such as aerospace – where flame retardant materials are used – as thoughts turn to an increased adoption of battery systems for electric and autonomous vehicles. DuPont's electronics business also brings materials that can be customized to work within EVs. The company recently expanded capacity for its high-temperature nylon compounds, adding that adhesives also will play a critical role.

"There's going to be more complexity,” says Toccalino. "A lot of the technology we talk about when we talk about electric or autonomous vehicles could and will come in from consumer electronic applications. If you think about the development cycle there versus the lifecycle of an automobile, they're very different. But this is where we have a fantastic opportunity because we play in both."