The plastic-like rectangles on the desk of Dr. Stephan Rudykh, from the aerospace engineering department of the Technion – Israel Institute of Technology, don’t look like big news or a future revolutionary innovation. Made of layers of transparent or semi-transparent polymers, they were created by means of a 3-D printer on the basis of theoretical models devised by Rudykh. But their bland appearance is misleading. Each piece of these materials represents years of research and engineering technology, which will ultimately change the way we perceive inanimate materials. Each of them possesses different mechanical and electrical properties.
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Pressing on one of the rectangles at a certain point leaves the material indifferent, but pressing at a different point causes it to bend and elevate. This, indeed, is the principal property of what are called “anisotropic” materials: Their qualities change in accordance with action and direction. In the meantime, these are only appetizers, prefigurings of the future material world that Rudykh – who for the past year has been cobbling together his new laboratory at the Technion – is planning. His research involves the development of multifunctional materials that will be used to develop artificial muscles, sensors and flexible robots that can alter their shape.
One of the projects he is currently working on involves the development of what are called active materials that will isolate noises selectively. “Imagine you’re in your office, where the walls are covered with a thin layer of special material. If you want to hold a discreet conversation that cannot be overheard, you press a button that makes the walls impervious to sound waves I created a situation in which sound waves cannot pass through this material.”
The project has drawn the interest of European automobile manufacturers, who would like to isolate engine noise with the use of advanced lightweight materials, instead of heavy ones, and that will also result in reduced fuel consumption.
Rudykh, who is only 33, received his bachelor and master’s degrees from St. Petersburg State Polytechnical University before his 23rd birthday. He immigrated to Israel in 2004 and obtained a Ph.D. from Ben-Gurion University in Be’er Sheva for a thesis dealing with electroactive composites. At the same time, he was involved in research at Caltech and at Harvard. Rudykh’s work focuses on the link between material microstructures and macroscopic properties – the latter referring to the connection between the particle structure of materials and the properties of large units of material.
What are we actually talking about here? The idea is that in the foreseeable future we will see materials that are less “indifferent” and far “smarter,” more sensitive and more active. They will be able to change their shape, their color and additional properties in response to an environmental situation or to electrical fields and impulses. To that end, scientists like Rudykh are probing, studying and redesigning the structures of complex substances.
His research directions are many and varied. He emphasizes constantly that his projects are still in a nascent state, but the imagination is always racing a few steps ahead.
“One can conceive of robots that are made of one unit of soft material and are capable of changing their shape. They might have a sensor and a small electronic system, and they could maybe enter into very narrow spaces, like an octopus, perhaps to rescue someone, or for some other purpose,” Rudykh says.
“The better we understand the connection between the molecular structure of matter and its properties at the macro level, the better we can control the functions we ‘extract’ from it – wavelengths, flexibility, electrical current and so on,” he continues.
“We can thus, for example, control light reflections and the color of material, or we can create a ‘wall of sound’ that blocks all the sound waves that encounter it – something we would want in earplugs, for example. This is actually a new direction for soft mechanization and soft robotics.”
The ability of material to respond actively to electrical fields make Rudykh’s research relevant in the realm of biomedicine as well. An example would be the creation of artificial muscles that react well to electrical impulses from the brain.
Materials research and development is where chemistry, biology and physics converge. The engineering of advanced materials with the use of complex chemical processes has been taking place for years in research and in industry, as well as in the commercial, security, medical and consumer-goods realms. A significant breakthrough was made possible by the development of technological abilities to carry out processes and manipulations at the level of individual molecules, along with the nanotechnology sciences, which opened the research door to processes taking place on a minute scale.
The next leap in materials development, of which Rudykh’s work is only an example, probes the reciprocal relations and the physical processes in the basic structures of materials, and adds another dimension to materials research and development.
“One of the things we are exploring is how different waves progress in move through material – sound waves or electromagnetic waves. As a random example, given that we can learn about the composition of biological tissue by examining the behavior of sound waves within it, we will be able to carry out noninvasive imaging, which will be far more precise and detailed than the existing ultrasound technologies,” the scientist explains.
The applications of the ability to change the way that waves pass through material will not remain confined to the medical field; scientists are already looking at how to apply the new developments in other areas. Thus, an electrical field could change material in a way that will recolor it.
“For example, you could make camouflage clothing that would change its colors, and allow soldiers to blend into their surroundings like chameleons,” Rudykh says.
He’s also working on development of additional properties that will enable the manufacture of flexible materials for defense in battle. In the future, these will replace the heavy, ceramic-armor protective vests that hinder soldiers’ movements.
“We are in the stage of initial testing, for which we used 3-D printing, and we’ve seen that it is a viable defense technology,” Rudykh notes. (In general, the development of 3-D printing technology is what has made possible for his theoretical models to take on substance.)
Theoretically, the world of active materials, as described by Rudykh, is almost unlimited. If the technology can breathe life into familiar inanimate objects, we can look forward to a world in which a wall is not only a wall – and not in the philosophical or conceptual sense.
“We are at a critical way station – a revolution of materials,” Rudykh sums up. “As soon as we achieve good control of the properties of material through its microstructure, we will be able to create materials of a completely different kind. Over and above the fact that they will be lighter, cheaper, stronger and more durable, we are talking about materials with abilities of adaptation and personal compatibility with people and their surroundings.”