Diverse Carbon Nanotube Artificial Muscles Meet an Exciting New Family Member - Ray Baughman
From Katie Gentilello
Humankind has had little success in replicating the wondrous properties of natural muscle, which has meant that the most advanced prosthetic limbs, exoskeletons, and humanoid robots lack critically needed capabilities. Use of electrical input power, instead of nature’s choice of high energy density fuel, is a problem for autonomous operation, which severely limits operational lifetime between recharge. Another problem is the inability to crowd sufficient motors into available space to provide natural movement. Probably no other material has been described for so many fundamentally different types of actuators than carbon nanotubes. Demonstrated electrically powered and fuel powered nanotube actuators provide up to a few percent actuator stroke and a hundred times higher stress generation than natural muscle. Large stroke pneumatic nanotube actuators have been demonstrated that use electrochemical gas generation within nanotube sheets. In other studies, nanotubes have been used either as electrodes or as additives to profoundly modify the response of other actuating materials – like dielectric, ionically conducting, photoresponsive, shape memory, and liquid crystal polymers. All of these advances will be discussed, together with most recent improvements. Most important, totally new types of carbon nanotube muscles will be described. These nanotube muscles provide over 300% actuator stroke, over 104 %/minute stroke rate and can be operated from near 0 K to far above the demonstrated 1900 K.