A bullet-proof heating pad

October 31, 2018, American Chemical Society
A bullet-proof heating pad
Credit: American Chemical Society

Sometimes nothing feels better on stiff, aching joints than a little heat. But many heating pads and wraps are rigid and provide uneven warmth, especially when the person is moving around. Researchers have now made a wearable heater by modifying woven Kevlar fabric with nanowires that conduct and retain heat. They report their results in ACS' journal Nano Letters.

Even at rest, the human body produces a lot of , but most of this warmth dissipates to the air and is wasted. Cold-weather clothing is often made from that keep heat close to the body, offering thermal insulation. For even more warmth, scientists have tried coating textiles with metallic nanowires that can be heated with a small battery. However, researchers are still searching for a material that provides good thermal conductivity and insulation while being safe, inexpensive, durable and flexible. Hyung Wook Park and colleagues wondered if they could make a wearable heating device by incorporating metallic nanowires into Kevlar, the famous bullet-proof fiber used in many types of body armor.

To make their wearable heater, the team grew copper-nickel nanowires between two Kevlar sheets. They filled in the spaces between the nanowires with a resin containing reduced graphene oxide to encourage uniform heating. Applying a low voltage (1.5 volts) to the composite material caused a rapid and uniform increase in surface temperature to 158 F—a typical "high" setting on a heating pad. In another experiment, the team showed that the material acted as a thermal insulator by reflecting infrared radiation emitted from a hot plate set at temperature.

The fabric was strong, flexible, breathable and washable, while still absorbing impacts similar to regular Kevlar. In addition to wearable heat therapy, the new material could be used to make heated armor for police and military personnel in cold climates, the researchers say.

Explore further: Pearly material for bendable heating elements

More information: Ankita Hazarika et al. Woven Kevlar Fiber/Polydimethylsiloxane/Reduced Graphene Oxide Composite-Based Personal Thermal Management with Freestanding Cu–Ni Core–Shell Nanowires, Nano Letters (2018). DOI: 10.1021/acs.nanolett.8b02408

Related Stories

Pearly material for bendable heating elements

January 24, 2018

The iridescent shimmer of a string of pearls may one day be more than pretty adornment. Scientists now report in ACS Applied Nano Materials a hybrid material consisting of imitation pearl combined with silver nanowires that ...

A stretchy mesh heater for sore muscles

July 3, 2015

If you suffer from chronic muscle pain a doctor will likely recommend for you to apply heat to the injury. But how do you effectively wrap that heat around a joint? Korean Scientists at the Center for Nanoparticle Research, ...

Recommended for you

'Smart skin' simplifies spotting strain in structures

November 15, 2018

Thanks to one peculiar characteristic of carbon nanotubes, engineers will soon be able to measure the accumulated strain in an airplane, a bridge or a pipeline – or just about anything – over the entire surface or down ...

Stealth-cap technology for light-emitting nanoparticles

November 14, 2018

A team of scientists from the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), in collaboration with researchers from Monash University Australia, has succeeded in significantly increasing the stability and biocompatibility of ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

Osiris1
1 / 5 (1) Nov 01, 2018
Most heating pads are designed to be laid on while in bed, so I suppose this inventor wanted to protect folks from assassins hiding under the bed. Typical republicans.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.