The researchers developed a synthetic system that reacts to environmental changes (The series is inspired by life and fits in with its surroundings) in the same way as living things, using feedback loops to maintain the internal conditions. Not only does this make the material stable, but also allows to build systems that react to their environment, an important quality for interactive and soft robotics.
Living systems, from individual cells to tissues, use feedback systems to maintain their condition. For example, we sweat to cool ourselves when we get too hot, and different mechanisms work to keep our blood flow and chemistry in the right range. . These homeostatic mechanisms make organisms resilient by helping them cope with changes in their environment. Although feedback is important in some mechanical systems, such as thermostats, they cannot change or stabilize the homeostatic system.
Now researchers from Aalto University and the University of Tampere have developed a system of materials that retain their state in a way similar to a living system. The new system consists of two side-by-side gels with different properties. The interaction between the gels makes the system react to changes in the environment, keeping its temperature within a narrow range when the laser is activated.
Hang Zhang, a postdoctoral researcher at the Academy of Finland and Aalto and one of the leading authors of the study said: “The tissues of living things are usually soft, flexible and deformed. ” “The gels used in our system are similar. They are soft polymers that dissolve in water, they can give a variety of interesting responses to environmental stimuli.
A laser shines through the first gel, then bounces off the glass in the second gel, where it heats the suspended gold nanoparticles. Heat flows from the second gel to the first, raising its temperature. The first gel becomes clear only when it is under a certain temperature; as soon as it heats up, it becomes negative. This switch prevents the laser from reaching the glass and heats the second gel. Both gels are cool until the first one is exposed again, where the laser passes and the heating process starts again.
In other words, the arrangement of the laser, gels, and mirror creates a feedback loop that causes the gels to heat up. At high temperatures, the laser is blocked and does not heat the gold nanoparticles; at low temperature, the first gel becomes transparent, so the laser shines and heats the gold material. “Like a living system, our home system can. The temperature fluctuates around the door, but the oscillations are small and strong in external disturbances. It’s a strong residential system,” said Hao Zeng, a researcher at the Academy of Finland and the University of Tampere, who is another author of the study.
The researchers then fixed the tactile stimuli on top of the feedback system. To do this, they added materials that react to temperature changes. Touching the gel system in the right way causes it to leave the stable state, and the resulting temperature change causes the active part to explode. Then everything returns to its original state.
The team designed two systems that accommodate different types of touch. Sometimes a single touch triggers a response, like a mimosa plant that doesn’t touch me bends its leaves when touched. The second configuration only accepts repeated touches, as a single Venus flytrap needs to be touched twice within 30 seconds to make it close. “We can trigger the clicking action by using a key to activate it at the right time, like the Venus flytrap. Our mechanical system can distinguish between short-term and high-intensity touch,” Professor Arri Priimägi of the University of Tampere explains.
The researchers also showed how the homeostatic system can control the dramatic color display or even transfer the load to the body part. They point out that these shows only show a few of the possibilities that the new concept opens up. Professor Olli Ikkala of Aalto University said.
“The inspired materials provide new examples of flexible and flexible materials that will attract researchers for years to come. “Carefully designed systems that mimic some of the fundamental characteristics of living systems will pave the way for truly intelligent objects and soft plastic interactions.”
The research was published in Nature Nanotechnology.
