The hollow bioinspired carbon tube aerogel. Credit: Hui-Juan Zhan
“Thanks to its unique microstructure, the CTA boasts excellent thermal insulation properties and is super-elastic,” explains Yu. Indeed, it has rebounding speed of 1434 mm/s, which is the fastest of all traditional elastic materials as measured using a standard test involving a falling steel ball. This makes it even more elastic than polar bear hair itself.
Its excellent thermal conductivity, which is lower than that of dry air, at just 23 mW/m/K comes from the hollow structure of the carbon tubes. This is because their inner diameter (of 35 nm) is smaller than the mean free path of air (75 nm). The thermal conductivity of the material remains intact even after being stored for 120 days at 56% relative humidity at room temperature in air
Robust mechanical structure
The CTA is also lightweight with a density of 8 kg/m3, which is lighter than most reported thermally insulating materials and is non-wettable at a contact angle of 146°, adds Yu. And remarkably, it maintains its mechanical structure even after more than one million compress-release cycles at 30% strain and 10 000 cycles at 90% strain.
The researchers, reporting their work in Chem 10.1016/j.chempr.2019.04.025, expect the material to find applications in the aerospace industry, especially in extreme environments. Before such applications see the light of day, however, they will need to scale up its manufacture to industrial scales, they say.
“The diameter of our CTA is 4 cm and its height around 2 cm,” explains Yu. “While it is difficult to obtain larger CTAs at the moment because of the size limitations of the laboratory equipment we employed, we hope to solve this problem by collaborating with industrial partners,” he tells Physics World.
On May 11, the Nature Publishing Group released Nature Publishing Index 2010 China, remarking “a dramatic rise in the quality of research being published by China”. University of Science and Technology of China is ranked 3rd of TOP 10 Institutions in Index 2010 China.