The Secret to Superwarm, Breathable Fabric Is a Tiny Amount of Silver

By Sarah Zhang on at

In the cold doldrums of January, any warm news is good news. Scientists at Stanford have unveiled a new clothing material made of cotton coated in silver nanowire. This fabric is breathable, lightweight, and incredibly warm.

So why silver? The metal naturally reflects infrared radiation back towards your body. But metal armor is definitely not comfortable, so the researchers dipped cotton fabric into a solution of silver nanowires. The resulting fabric traps 80 perc ent of body heat, equivalent to the upper end of a (much bulkier) fleece. Surprisingly, the amount of silver needed to cover clothing for the whole body would only be about 66p, the study's author tells Popular Science.

Since silver is naturally conductive, a tiny amount of electricity could also turn a shirt of such material into essentially a wearable electric blanket. And because this fabric is also more breathable and lightweight than you typical cold-weather gear, the researchers suggest a toasty shirt could replace indoor heating. That claim, though, seems contingent on people actually being willing to wear gloves and hats indoors. The tech alone won't save energy, but perhaps it can nudge people toward lifestyles of greater energy efficiency (and lower heating bills).

We've also seen silver in clothing before, but for an entirely different purpose. Because silver is also a pretty powerful antimicrobial, nanoparticles of the metal have been turning up in "anti-stink" gym clothes. That's raised some questions about the (yet-to-be-confirmed) safety of tiny pieces of silver sloughing off onto your skin, which this fabric will need to be tested for as well.

For now, I'm hunkered down with my Snuggie and my wool socks, and I await a warmer, less bulky future. [Nano Letters via Popular Science]

Top image: Silver nanowire-coated fabric. Hsu et al. /Nano Letters