Enhancing the electromechanical behavior of a flexible polymer
Researchers improved the material's electricity generation efficiency by
60%

Date:
March 24, 2022
Source:
Penn State
Summary:
Piezoelectric materials convert mechanical stress into electricity,
or vice versa, and can be useful in sensors, actuators and many
other applications. But implementing piezoelectrics in polymers
-- materials composed of molecular chains and commonly used in
plastics, drugs and more -- can be difficult.



FULL STORY ========================================================================== Piezoelectric materials convert mechanical stress into electricity,
or vice versa, and can be useful in sensors, actuators and many other applications. But implementing piezoelectrics in polymers -- materials
composed of molecular chains and commonly used in plastics, drugs and
more -- can be difficult, according to Qiming Zhang, distinguished
professor of electrical engineering.


========================================================================== Zhang and a Penn State-led team of interdisciplinary researchers developed
a polymer with robust piezoelectric effectiveness, resulting in 60%
more efficient electricity generation than previous iterations. They
published their results today (Mar. 25) in Science.

"Historically, the electromechanics coupling of polymers has been
very low," Zhang said. "We set out to improve this because the relative softness of polymers makes them excellent candidates for soft sensors and actuators in a variety of areas, including biosensing, sonar, artificial muscles and more." To create the material, the researchers deliberately implemented chemical impurities into the polymer. This process, known
as doping, allows researchers to tune the properties of a material to
generate desirable effects -- provided they integrate the correct number
of impurities. Adding too little of a dopant could prevent the desired
effect from initiating, while adding too much could introduce unwanted
traits that hamper the material's function.

The doping distorts the spacing between positive and negative charges
within the polymer's structural components. The distortion segregates
the opposite charges, allowing the components to accumulate an external electric charge more efficiently. This accumulation enhances electricity transfer in the polymer when it is deformed, Zhang said.

To enhance the doping effect and ensure alignment of the molecular chains,
the researchers stretched the polymer. This alignment, according to Zhang, promotes more of an electromechanical response than from a polymer with randomly aligned chains.

"The efficiency of the polymer's electricity generation was vastly
increased," Zhang said. "With this process, we achieved a 70% efficiency
-- a vast improvement from 10% efficiency before." This robust
electromechanic performance, which is more common in stiff ceramic
materials, could enable a variety of applications for the flexible
polymer.

Because the polymer exhibits resistance to sound waves similar to that of
water and human tissues, it could be applied for use in medical imaging, underwater hydrophones or pressure sensors. Polymers also tend to be
more lightweight and configurable than ceramics, so this polymer could
provide opportunities to explore improvements in imaging, robotics and
more, Zhang said.

Other contributors to this work include Xin Chen, with the Penn State Department of Materials Science and Engineering in the College of
Earth and Mineral Sciences; Hancheng Qin, Bing Zhang, Wenchang Lu and
J. Bernholc with North Carolina State University; Xiaoshi Qian with
Shanhai Jiao Tong University in China; Wenyi Zhu with the Penn State
School of Electrical Engineering and Computer Science; Bo Li and Shihai
Zhang with PolyK Technologies in State College; Ruipeng Li with Brookhaven National Laboratory; Lei Zhu with Case Western Reserve University; and
Fabrice Domingues Dos Santos with Arkema in France. Qiming Zhang is also affiliated with the Materials Research Institute at Penn State.

The U.S. Office of Naval Research supported this work.


========================================================================== Story Source: Materials provided by Penn_State. Note: Content may be
edited for style and length.


========================================================================== Journal Reference:
1. Xin Chen, Hancheng Qin, Xiaoshi Qian, Wenyi Zhu, Bo Li, Bing Zhang,
Wenchang Lu, Ruipeng Li, Shihai Zhang, Lei Zhu, Fabrice Domingues
Dos Santos, J. Bernholc, Q. M. Zhang. Relaxor ferroelectric polymer
exhibits ultrahigh electromechanical coupling at low electric
field. Science, 2022; 375 (6587): 1418 DOI: 10.1126/science.abn0936 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220324143755.htm

--- up 3 weeks, 3 days, 10 hours, 51 minutes
* Origin: -=> Castle Rock BBS <=- Now Husky HPT Powered! (1:317/3)