Ice has a tendency to crack into shards. Try to bend an icicle, and it’ll snap in two. So ice’s reputation for being stiff and brittle seems well-established. But thin, pristine threads of ice are bendy and elastic.
Peizhen Xu and his colleagues reported their find on July 9 in Science. Xu is a physicist at Zhejiang University. That is in Hangzhou, China.
To create the flexible ice, the scientists applied an electric voltage to a needle within a chilled chamber. This electrified needle attracted water vapor. That water vapor transformed into very thin ice whiskers. The ice was a few micrometers in diameter or less. That’s a fraction the width of a typical human hair.
Usually, ice contains defects — tiny cracks, pores or misaligned sections of crystal. But these specially grown ice threads consisted of near-perfect ice crystals. And they had odd properties. The scientists manipulated the ice at temperatures of –70° Celsius (–94° Fahrenheit) and –150 °C (–238 °F). At these very cold temps, the ice could be curved into a partial circle with a tiny radius of just tens of micrometers. When the bending force was released, the fibers sprang back to their original shape.
Bending the fibers compresses the ice on its inside edge. The new measurements indicate that the compression induces the ice to take on a different structure. That’s to be expected for ice. Ice is known to morph into a variety of phases depending on pressure and temperature. The new bendy ice discovery could give researchers a new way to study ice’s properties when squeezed.
Thin ice strands also form naturally in snowflakes. Unlike the ice in the experiment, snowflakes don’t consist of single, flawless ice crystals. But small sections of the flakes could be single crystals, the researchers say. That suggests that tiny bits of snowflakes might also bend.