Actuation of ferroelectric polymers pushed by Joule heating. Credit score: Qing Wang
A brand new ferroelectric polymer that effectively converts electrical power into mechanical pressure has been developed by Penn State researchers. This materials, exhibiting potential to be used in medical units and robotics, overcomes conventional piezoelectric limitations. Researchers improved efficiency by making a polymer nanocomposite, considerably decreasing the required driving discipline power, increasing potential functions.
A brand new sort of ferroelectric polymer that’s exceptionally good at changing electrical power into mechanical pressure holds promise as a high-performance movement controller or “actuator” with nice potential for functions in medical units, superior robotics, and precision positioning techniques, in response to a workforce of worldwide researchers led by Penn State.
Mechanical pressure, how a fabric modifications form when pressure is utilized, is a vital property for an actuator, which is any materials that can change or deform when an exterior pressure comparable to electrical power is utilized. Historically, these actuator supplies have been inflexible, however comfortable actuators comparable to ferrroelectric polymers show increased flexibility and environmental adaptability.
The analysis demonstrated the potential of ferroelectric polymer nanocomposites to beat the constraints of conventional piezoelectric polymer composites, providing a promising avenue for the event of soppy actuators with enhanced pressure efficiency and mechanical power density. Smooth actuators are particularly of curiosity to robotics researchers attributable to their power, energy, and suppleness.
“Probably we will now have a sort of soppy robotics that we seek advice from as synthetic muscle,” stated Qing Wang, Penn State professor of supplies science and engineering and co-corresponding writer of the examine lately revealed within the journal Nature Supplies. “This could allow us to have comfortable matter that may carry a excessive load along with a big pressure. In order that materials would then be extra of a mimic of human muscle, one that’s near human muscle.”
Nonetheless, there are just a few obstacles to beat earlier than these supplies can meet their promise, and potential options to those obstacles have been proposed within the examine. Ferroelectrics are a category of supplies that exhibit a spontaneous electrical polarization when an exterior electrical cost is utilized and optimistic and unfavourable prices within the supplies head to completely different poles. Pressure in these supplies in the course of the part transition, on this case conversion {of electrical} power to mechanical power, can fully change properties comparable to its form, making them helpful as actuators.
“Probably we will now have a sort of soppy robotics that we seek advice from as synthetic muscle.”
— Qing Wang, professor of supplies science and engineering
A standard utility of a ferroelectric actuator is an inkjet printer, the place electrical cost modifications the form of the actuator to exactly management the tiny nozzles that deposit ink on the paper to type textual content and pictures.
Whereas many ferroelectric supplies are ceramics, in addition they may be polymers, a category of pure and artificial supplies product of many comparable items bonded collectively. For instance, DNA is a polymer, as is nylon. An advantage of ferroelectric polymers is they exhibit a tremendous amount of the electric-field-induced strain needed for actuation. This strain is much higher than what is generated by other ferroelectric materials used for actuators, such as ceramics.
This property of ferroelectric materials, along with a high level of flexibility, reduced cost compared to other ferroelectric materials, and low weight, holds great interest for researchers in the growing field of soft robotics, the design of robots with flexible parts and electronics.
“In this study, we proposed solutions to two major challenges in the soft material actuation field,” said Wang. “One is how to improve the force of soft materials. We know soft actuation materials that are polymers have the largest strain, but they generate much less force compared to piezoelectric ceramics.”
The second challenge is that a ferroelectric polymer actuator typically needs a very high driving field, which is a force that imposes a change in the system, such as the shape change in an actuator. In this case, the high driving field is necessary to generate the shape change in the polymer required for the ferroelectric reaction needed to become an actuator.
The solution proposed to improve the performance of ferroelectric polymers was developing a percolative ferroelectric polymer nanocomposite — a kind of microscopic sticker attached to the polymer. By incorporating nanoparticles into a type of polymer, polyvinylidene fluoride, the researchers created an interconnected network of poles within the polymer.
“…this new material can be used for many applications that require a low driving field to be effective, such as medical devices, optical devices and soft robotics.”
— Qing Wang, professor of materials science and engineering
This network enabled a ferroelectric phase transition to be induced at much lower electric fields than would normally be required. This was achieved via an electro-thermal method using Joule heating, which occurs when electric current passing through a conductor produces heat. Using the Joule heating to induce the phase transition in the nanocomposite polymer resulted in only requiring less than 10% of the strength of an electric field typically needed for ferroelectric phase change.
“Typically, this strain and force in ferroelectric materials are correlated with each other, in an inverse relationship,” Wang said. “Now we can integrate them together into one material, and we developed a new approach to drive it using the Joule heating. Since the driving field is going to be much lower, less than 10%, this is why this new material can be used for many applications that require a low driving field to be effective, such as medical devices, optical devices, and soft robotics.”
Reference: “Electro-thermal actuation in percolative ferroelectric polymer nanocomposites” by Yang Liu, Yao Zhou, Hancheng Qin, Tiannan Yang, Xin Chen, Li Li, Zhubing Han, Ke Wang, Bing Zhang, Wenchang Lu, Long-Qing Chen, J. Bernholc and Qing Wang, 25 May 2023, Nature Materials.
DOI: 10.1038/s41563-023-01564-7
Along with Wang, other researchers in the study include from Penn State Yao Zhou, postdoctoral scholar in materials science and engineering; Tiannan Yang, assistant research professor with the Materials Research Institute; Xin Chen, postdoctoral researcher in materials science and engineering; Li Li, research assistant in materials science and engineering; Zhubing Han, graduate research assistant in materials science and engineering; Ke Wang, associate research professor with the Materials Research Institute; and Long-Qing Chen, Hamer Professor of Materials Science and Engineering. From North Carolina State University, other researchers in the study include Hancheng Qin, graduate research assistant in physics; Bing Zhang, graduate student in physics; Wenchang Lu, research professor in physics; and Jerry Bernholc, Drexel Professor in Physics. From Huazhong University of Science and Technology in Wuhan, China, other researchers in the study include co-corresponding author Yang Liu, a former postdoctoral scholar in materials science and engineering at Penn State, now a professor of materials science and engineering.
The study was supported in part by the United States Department of Energy.