Intelligent materials help in space and directly in the body
Smart materials react to external influences as sensors and also as actuators. The Smart Materials Summit shows fields of application for aerospace and medicine.
The start-up Reflex Aerospace is working on small satellites. Smart materials help to make functions in space particularly compact.
(Image: Reflex Aerospace)
When materials react in a repeatable way to external influences such as heat or light, electric or magnetic fields, this opens up various applications. So-called smart materials can serve as sensors and react to heat and pressure with electrical impulses, for example. They can also be used directly as actuators, for example when shape memory alloys return to their predetermined shape in response to a thermal or electrical stimulus.
These effects can be used to build particularly compact satellites or smart implants that accelerate the healing of bone fractures, for example. Even touch can be translated into transmittable signals by smart materials on the one hand, and on the other hand can be output again in the form of pressure or vibrations using controllable foils.
Smart materials in orbit
Together with the innovation network smart3 e.V. in Bautzen, Saarland University is organizing the Smart Materials Summit in SaarbrĂĽcken on 7 and 8 November 2024. "One highlight of the Smart Materials Summit is the New Space area," reports Paul Motzki, Professor of Smart Materials Systems at the organizing university's Intelligent Material Systems Lab. For example, it is difficult to efficiently cool the very compact satellites used in modern space travel. "There is no convection in space," says Motzki, satellites cannot draw in a cool medium in orbit. Solid-state cooling technology promises to help. Motzki's researchers have developed a heat pump technology with elastocalorics; their material becomes warm under pressure and cold again when the pressure is released. Such wires can dissipate heat in a targeted manner, more energy-efficiently than today's heat pumps and without additional refrigerants that are harmful to the climate.
As a spin-off of the Karlsruhe Institute of Technology (KIT), Memetis is working on shape memory alloys. The Karlsruhe-based company uses them to build ultra-compact micro valves for optical and aerospace applications, for example. Microactuators control lab-on-a-chip systems in the smallest of spaces.
Shape memory against heat
Researchers at the Fraunhofer Institute for Machine Tools and Forming Technology are also working on shape memory actuators. For example, they have developed a smart façade for the solar protection of glass façades. Wires made from a nickel-titanium alloy return to their original shape when heated, unfolding textile screens that shade the building before it heats up and the air conditioning kicks in.
In medical technology, a team led by Motzki is pinning its hopes on implantable actuators that can stimulate bone growth in fractures, for example, through micro-movements in the fracture gap. The smart material used could also serve as a sensor that recognizes early on whether bone growth is starting as desired.
Another field of application for smart materials could be the transmission of vibrations and strokes. For example, researchers at the Intelligent Material Systems Lab are working with thin polymer films that vibrate when stimulated. These films can not only enhance the function of touchscreens. Woven into textiles, it is possible to simulate caresses. With a corresponding item of clothing on the transmitter, it could be possible in future to record touches, transmit them online and play them back.
(agr)