Science 330, 1364–1368 (2010)

Viscoelastic materials such as rubber can both recover their shape when a stress is removed (elasticity) and dissipate energy (viscosity), making them useful dampers of vibration and sound. However, these properties are usually temperature dependent. For example, silicone rubber hardens at −55 °C and degrades at 300 °C. Now Kenji Hata and co-workers at AIST and JST in Japan have demonstrated a viscoelastic material made from carbon nanotubes with a much wider functional temperature range.

The material consists of long nanotubes with a high density of physical interconnections, analogous to a clump of hair. Electron microscope images show the randomly aligned and tangled nanotubes reversibly straightening in the direction of applied strain, for strains up to 5%. The viscoelastic properties are similar to those of silicone rubber, but constant from −196 °C to 1,000 °C, with these temperatures limited by the measuring instrumentation. The material also allows for the rapid dissipation of heat, which is a common cause of degradation, and its properties can be tuned by varying the nanotube density.