The gear is one of the oldest mechanical devices in human history and led to machines ranging from modern irrigation systems and clocks to modern engines and robotics. For the first time, researchers at the University of Pittsburgh Swanson School of Engineering have used a catalytic reaction to “morph” a two-dimensional, chemically coated sheet into a three-dimensional gear that works continuously.
The findings indicate the ability to develop chemically powered machines that do not rely on external power, but only require the addition of reactants to the surrounding solution. Published today in SAIL Press Journal matterAna c the research. Balazs, Distinguished Professor of Chemical and Petroleum Engineering and John A. Was developed by the Swanson Chair of Engineering. Lead writer Abrajeet Laskar and co-author Oleg E. There is Shakaliyav, who is both a doctoral associate.
Balazs explains, “Gears help give mechanical life to machines; however, they require some kind of external power to perform a task, such as steam or electricity. It operates in resource-poor or remote environments Vali limits the capacity of future machines, ”explains Balazs. “Abrajit’s computational modeling has shown that chemo-mechanical translocation (converting chemical energy into motion) on an active sheet presents a new way to replicate the behavior of gears in environments without access to conventional power sources.”
In the simulation, the catalyst is placed at various points on a two-dimensional sheet, which is like a wheel with spokes, with heavy nodes on the circumference of the sheet. The flexible sheet, which is approximately one millimeter in length, is then placed in a fluid-filled microbeactor. A reactive chamber is added that activates the catalyst on the flat “wheel”, allowing the fluid to flow spontaneously. The flow of incoming fluid drives the lighter sections of the sheet to pop up, creating an active rotor that captures and rotates the flow.
“What’s really specific about this research is the coupling of deformation and propulsion to modify the shape of the object to create movement,” Lasker says. “The deformation of the object is the main one; we see in nature that organisms use chemical energy to change their shape and speed. To move our chemical sheet, it has to spontaneously change to a new shape, which makes it Allows fluid to hold the flow. And its function. “
Additionally, Laskar and Shakliav found that not all gear parts are required for the motion to be chemically active; In fact, asymmetry is important for creating movement. By determining the design rules for placement, Lasker and Shakliav can direct the rotation to be clockwise or counterclockwise. This additional “program” enabled the control of independent rotors, with active or passive gear systems, to move independently or in a cascade effect. This more complex action is controlled by the internal structure of the spokes, and the placement within the fluid domain.
“Because a gear is a central component to any machine, you need to start from the basics, and what Abrajit has built is like an internal combustion engine on the millimeter scale,” says Shakilav. “While it will not power your car, it presents the ability to build basic mechanisms to run small-scale chemical machines and soft robots.”
In the future, Balazs will examine how spatial organization relative to multiple gears may lead to greater functionality and potentially to design a system as if it were making a decision.
“The more remote the machine is from a human control, the more you need the machine to provide control to accomplish a given task,” Balazs said. “The chemo-mechanical nature of our equipment allows it to occur without any external power source.”
These self-morphing gears are the latest development of chemo-mechanical processes developed by Balasz, Laskar and Shakilv. Other advances include making crab-like sheets that mimic feed, flight, and fight responses; And the sheets resemble “flying carpets” that wrap, flap and creep.
Chemical engineered catalysts replicate feed, fight, and flight reactions in chemical reactions
matter (2020). DOI: 10.1016 / j.matt.2020.11.04, www.cell.com/matter/fulltext/S2590-2385(20)30631-7
Provided by the University of Pittsburgh
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