Tech Briefs Magazine - May 2022 - 40

Materials & Coatings
The team designed, fabricated, and
tested a flexible LIG pressure sensor. For
the first design, they sandwiched a thin
LIG foam layer between two polyimide
layers
This design, when attached to the
containing copper electrodes.
When pressure was applied, the LIG generated
electricity. The voids in the foam
reduced the number of pathways for
electricity to travel, making it easier to localize
the pressure source, and appeared
to improve sensitivity to delicate touches.
back of the hand or the finger, detected
bending and stretching hand movements
as well as the characteristic percussion,
tidal, and diastolic waves of the
heartbeat. This pulse reading could be
combined with an electrocardiogram
reading to yield blood pressure measurements
without a cuff.
ers
In the second design, the researchincorporated
nanoparticles
into
the
LIG foam. These tiny spheres of
molybdenum disulfide, a semiconductor
that can act as a conductor and an
insulator, enhanced the foam's sensitivity
and resistance to physical forces.
This design was also resilient to
repeated use, showing nearly identical
performance before and after nearly
10,000 uses.
For more information, contact Ben Manning
at bam58@psu.edu; 814-863-4713.
Developing a Flexible Polymer with Robust Piezoelectric
Effectiveness
The flexible polymer could provide opportunities to explore improvements in imaging,
robotics, and more.
Penn State University, University Park, PA
A
Penn State-led team of interdisciplinary
researchers developed a
polymer with robust piezoelectric effectiveness,
resulting in 60 percent more
efficient electricity generation than previous
iterations.
According to Qiming Zhang, distinguished
professor of electrical engineering
at Penn State, the electromechanics
coupling of polymers has been very low,
so they 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.
40
Qiming Zhang, distinguished professor of electrical engineering, led a team of researchers to develop
a robust piezoelectric material that can convert mechanical stress into electricity. (Photo: Tyler
Henderson/Penn State)
This alignment, according to Zhang,
promotes more of an electromechanical
response than from a polymer with randomly
aligned chains. The team achieved
70 percent efficiency with the process.
They published their results in Science.
This robust electromechanical performance,
which is more common in stiff
ceramic materials, could enable a variety
of applications for the flexible polymer.
Because the polymer exhibits resistance
www.techbriefs.com
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.
For more information, contact Media Relations
at communications@engr.psu.edu.
Tech Briefs, May 2022
TB Materials Coatings 0522_1.indd 40
Cov
ToC
4/19/22 8:25 AM

http://www.techbriefs.com http://info.hotims.com/82321-809

Tech Briefs Magazine - May 2022

Table of Contents for the Digital Edition of Tech Briefs Magazine - May 2022