Tech Briefs Magazine - August 2021 - 25

Materials & Coatings
Hybrid Thermoelectric Compound
The material sets the stage for new forms of electric power in the future.
Clemson University, Clemson, South Carolina
hermoelectrics directly convert heat
into electricity and power a wide ar -
ray of items, from NASA's Perse verance
rover currently exploring Mars to travel
coolers that chill beverages.
A material's atomic structure, which is
how atoms arrange themselves in space
and time, determines its properties.
Typically, solids are crystalline or amorphous.
In crystals, atoms are in an orderly
and symmetrical pattern. Amorphous ma -
terials have randomly distributed atoms.
Researchers have created a new hybrid
T
compound in which the crystalline and
amorphous sublattices are intertwined
into a crystal-amorphic duality.
The material is a unique hybrid atomic
structure with half being crystalline
and half amorphous. The researchers
created the hybrid material by intentionally
mixing elements in the same group
on the periodic table but with different
atomic sizes. They used the atomic size
mismatches between sulfur and tellurium
and between copper and silver to
create a new compound (Cu1-xAgx)2
(Te1-ySy) in which the crystalline and
amorphous sublattices intertwine into
the crystal-amorphicity duality.
The new compound exhibited excellent
thermoelectric performance but
more important than that is how it
achieves that level of performance.
Traditionally, thermoelectric materials
are crystals; however, the new material is
not pure crystal but it can achieve the
same level of performance.
For more information, contact Jian He,
Associate Professor, at jianhe@g.clemson.edu.
Nanoparticle Gel Unites Oil and Water in ManufacturingFriendly
Approach
This novel gel-creation method could open applications in water filtration, batteries, and
smart windows.
National Institute of Standards and Technology, Gaithersburg, Maryland
O
il and water may not mix but adding
the right nanoparticles to the recipe
can convert these two immiscible fluids
into an exotic gel with uses ranging from
batteries to water filters to tint-changing
smart windows.
Previous Gels
Such gels have been an area of re -
search for decades. Part of their potentially
broad utility is the complex set of
interconnected microscopic channels
that form within them, creating a sponge -
like structure. These channels not only
SeedGel
offer passageways for other materials to
travel through - making them useful for
filtration - but also give the gel a high
amount of internal surface area, a characteristic
valuable for speeding up chemical
reactions or as scaffolding on which
living tissue can grow.
Filtration
Smart Windows
Battery Technology
Tissue Engineering
The SeedGel is a
porous material with
tunable pore size.
It can switch from
transparent to opaque
and back again.
Its high surface area
can enhance the
capacity of batteries.
Its channels can serve
as scaffolds for cell
growth and delivery.
Unlike other gel-creation approaches where nanoparticles remain at the interface between the
gel's two constituent solvents (top left), the new approach concentrates nanoparticles in the interior
of one of the solvents (top right), giving the resulting SeedGel unusual mechanical strength.
(Credit: N.Hanacek/NIST)
Tech Briefs, August 2021
Cov
www.techbriefs.com
ToC
The gels are commonly formed of two
liquid solvents mingled together. As with
oil and water, these solvents do not mix
well but to prevent them from completely
separating, researchers add custom-de -
signed nanoparticles that can stay at the
interface between them. Carefully cooking
these ingredients allows a cohesive gel to
form; however, the process is demanding
because custom-designing nanoparticles
for each application has been difficult and
forming the gels has required carefully
controlled rapid temperature change.
These constraints have made it hard to
create this type of gel in any more than
small quantities suitable for lab experiments
rather than on an industrial scale.
Researchers have found ways to sidestep
many of these problems. The novel
approach they developed forms a
SeedGel - an abbreviation for solvent
25

http://www.techbriefs.com http://www.abpi.net/ntbpdfclicks/l.php?202108MDNAV

Tech Briefs Magazine - August 2021

Table of Contents for the Digital Edition of Tech Briefs Magazine - August 2021