Yi Rao, UC Berkeley1 Carbon Nanotube (CNT) Aerogel Muscles Yi Rao May 4th, 2008

Yi Rao, UC Berkeley2 By Ray H. Baughman, UT Dallas Natural MuscleCNT Aerogel Density (kg/m 3 ) Strain (%) Strain Rate (%/s)503.7×10 4 Stress (MPa) Work per Cycle (J/Kg)4030 Operating temp. (K)Ambient Cycle Life *10 6 k140k

Yi Rao, UC Berkeley3 Preparation of CNT Aerogel Sheet Actuator CNT Aerogel Sheet is drawn from straight sidewalls of MWNT Speed: 2m/s Outer diameter: 12nm with 9 walls MWNT forest were synthesized by catalytic CVD

Yi Rao, UC Berkeley4 Measurement of Actuation The CNT sheet is expanded by change repulsion Apply voltage to positively charge to CNT sheet Changes is recorded by optical diffraction

Yi Rao, UC Berkeley5 Actuation in width and thickness direction Voltage, L/W ratio and temperature dependence Sheets num

Yi Rao, UC Berkeley6 Operating at resonance with low voltage Q is 455, the strain can be 30% with V rms =10V

Yi Rao, UC Berkeley7 Actuation in the length direction (Strength) Different applied voltage to width expansion Stress on length direction and work capacity

Yi Rao, UC Berkeley8 Conclusion and Drawback The CNT Aerogel muscle shows some amazing properties compared with human muscle Strain, Strain Rate, Stress Density Temperature tolerance But there are still some concerns The material volume is not large and dense enough for real use The property of CNT sheet becomes worse when add more layers The apply voltage on low frequency is too large Very high cost ($100/g)

Yi Rao, UC Berkeley9 Complementary: Aerogel Aerogel is a solid-state material with the lowest known density Aerogel is gel in which the liquid component of the gel has been replaced with gas. Aerogel is thermal insulator