The team began by making a circular chamber just over an inch in diameter in a 3-D printer. Using liquid nitrogen, they cooled the space within the chamber to negative 58 degrees Fahrenheit. They then inserted tiny tools into this miniature laboratory, including a metal needle with 2,000 volts of electricity applied to it. That voltage created an electrical field, and water molecules present in the air responded to the field by settling on the needle. Very slowly, at a rate of roughly a hundredth of an inch per second, rodlike microfibers of ice grew from the tip of the needle.
The microfibers never got very long — they could barely be seen with the naked eye — but high-resolution imaging revealed that they were single crystals. That means that the atoms within them are arranged in repeating patterns. “The atoms are ordered like honeycombs,” Dr. Tong said.
This structural perfection, paired with the microfibers’ relative lack of microscopic defects — such as tiny cracks, pores and missing atoms or molecules — renders them much more flexible than naturally occurring ice, said Erland Schulson, an ice scientist at Dartmouth College, who was not involved in the research.
“There are no grain boundaries, no cracks, no features that otherwise limit how much elastic strain a body can experience.”