Carbon nanotubes and their composites for viscoelastic applications

Vibration-induced failure of devices has plagued the developers of mechanical systems since the development of early machinery. This problem has now manifested itself into design issues in small-scale mechanical devices. Since the first microelectromechanical device was reported in 1967, numerous issues with the longevity, energy lost, wear, instability and performance of these devices have been associated with parasitic vibration noises. This problem is especially acute now in the rapidly developing area of nanoelectromechanical systems because of the extreme surface-to-volume ratios these devices have. As such, numerous studies are currently devoted to improving the vibration damping in nano-devices. The traditional method for addressing these issues is to integrate dampers and low-friction materials together in a device. However, unlike macro environments, implementation of such protection on the sub-micrometer scale is either unfeasible or extremely costly because of the complex fabrication involved. A more reasonable solution is to use an intrinsic damping material built directly into the device for energy dissipation and load recovery. One promising solution is the use of carbon nanotubes and their composites. This is one of the main driving factors in the study of carbon nanotube films and carbon nanotube–polymer composites for their mechanical strength and viscoelastic properties. This chapter thus focuses on the strength and weaknesses associated with using carbon nanotubes and their composites in damping and viscoelastic applications.