Saturday, June 03, 2006

US Patent 7053520 - Nanotube Rotational Motor

Microelectromechanical actuators have several applications as drivers for optical switches and microfluidic valves. However, scaling down micromechanical structures to the nanoscale presents some problems including stiction (sticking) between the microstructural elements because of residual chemicals after a wet etch. Using nanostructures such as nanotubes for nanoelectromechanical actuators has previously been suggested as a solution to this problem. This patent teaches using a multiwall nanotube as a motor with the inner tubes as a stator and an outer tube as a rotor. High rotational degree of freedom is achieved by applying a high voltage to the stator and releasing the outer tube. Claim 1 reads:

1. A nanoscale device, comprising: (a) a substrate; (b) at least one anchor pad on the substrate; (c) a multiwalled nanotube mechanically connected to and extending from the anchor pad; (d) a rotor plate connected to a rotatable wall of the nanotube and positioned to rotate in conjunction with the nanotube and relative to the substrate; and (e) at least one stator electrode connected to the substrate, and disposed about the rotor plate to electrically interact therewith when charged with suitable voltage to cause rotational movement; said multiwalled nanotube having an outer shell that is compromised in a region between the rotor and the anchor pad to permit additional rotational freedom of the rotor.