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Carbon Nanotube (CNT) Aerogel Muscles

Yi Rao

May 4th, 2008

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By Ray H. Baughman, UT Dallas

Natural Muscle CNT Aerogel

Density (kg/m3) 1037 1.5

Strain (%) 20-40 220

Strain Rate (%/s) 50 3.7×104

Stress (MPa) 0.1-0.35 3.2

Work per Cycle (J/Kg) 40 30

Operating temp. (K) Ambient 80-1900

Cycle Life * 106k 140k

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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

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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

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Actuation in width and thickness directionVoltage, L/W ratio and temperature dependence

Sheets num

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Operating at resonance with low voltage

Q is 455, the strain can be 30% with Vrms=10V

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Actuation in the length direction (Strength)

Different applied voltageto width expansion

Stress on length direction and work capacity

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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)

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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