Lightweight electric wristband heaters for constant, portable warmth


Date:
October 20, 2021
Source:
American Chemical Society
Summary:
As the fall chill settles in across the U.S., people are getting
out their cozy sweaters and electric blankets, or stocking up on
handheld heat packets for extra warmth. But sweaters and blankets
are bulky, and heat packs only work for a little while. Now,
researchers demonstrate a conductive, durable yarn for lightweight
wearable heaters that are re- usable and provide constant,
portable warmth.



FULL STORY ==========================================================================
As the fall chill settles in across the U.S., people are getting out
their cozy sweaters and electric blankets, or stocking up on handheld
heat packets for extra warmth. But sweaters and blankets are bulky, and
heat packs only work for a little while. Now, researchers reporting in
ACS Applied Materials & Interfaces demonstrate a conductive, durable yarn
for lightweight wearable heaters that are re-usable and provide constant, portable warmth.


========================================================================== Lightweight wearable heaters with heating elements embedded within
the fabric could help keep people warm, but previous attempts
have resulted in hot stiff wires or threads that cannot be safely
washed. Recently, researchers have treated fabric and yarn with poly(3,4-ethylenedioxythiophene) and poly(4- styrenesulfonate). This
flexible coating warmed up the materials and stayed in place after
washing. However, the polymers were not conductive enough for personal
heating, and some compounds added to make them more conductive could
irritate the skin. So, Rawat Jaisutti and colleagues wanted to improve
upon the two-polymer coating applied to yarn so that it could distribute
heat at a safe operating voltage when sewn into fabric.

As a first step, the researchers dipped the polymer-coated cotton yarn
into ethylene glycol, which is not irritating to human skin. When they
applied voltage to the material, it warmed up, requiring lower voltages
to reach high temperatures than some previously reported flexible
heaters. Then the team washed treated yarn either repeatedly with water
or once with detergent. They found that although in both instances there
was a slight loss of conductivity, this loss was significantly less than
a version without the ethylene glycol.

Finally, the researchers sewed multiple pieces of the yarn into a "TU"
pattern on a bit of fabric with an additional fabric backing. When
the heater was connected to a three-volt power supply and attached to a person's wrist, the heat distribution in the thermal wristband was steady
as it was bent back and forth. The researchers say the wristband can
also be powered by a battery via an external circuit for more portability.

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


========================================================================== Journal Reference:
1. Kuntima Pattanarat, Nattasamon Petchsang, Tanakorn Osotchan,
Yong-Hoon
Kim, Rawat Jaisutti. Wash-Durable Conductive Yarn with Ethylene
Glycol- Treated PEDOT:PSS for Wearable Electric Heaters. ACS
Applied Materials & Interfaces, 2021; 13 (40): 48053 DOI:
10.1021/acsami.1c13329 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/10/211020135908.htm

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