Project #6Surface Modification of Carbon

Nanotubes for Property Improvement

Cuong Diep – pre-junior, Chemical EngineeringMilena Fernandez – pre-junior, Computer Engineering

College of Engineering and Applied Science; University of Cincinnati; Cincinnati, Ohio

Dr. Vesselin Shanov- Chemical and Materials Engineering, CEAS

Dr. Noe Alvarez- Chemical and Materials Engineering, CEAS

Sponsored ByThe National Science Foundation Grant ID No.: DUE-0756921

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Outline1. Goals and Objectives

2. Carbon Nanotubes (CNTs)

3. The processes of improving CNTs thread

– Densification

– Doping

– Coating

4. Integration of the transformer

5. CNT future applications

6. Summary

7. Conclusion 2

Goals• To design a transformer using CNTs thread

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Objectives

1. To design transformer2. To modify CNTs thread by the processes of

densification, doping and coating. 3. To wind CNTs thread on transformer.4. To induce voltage to transformer and power up a

light source.

CNTs- Carbon nanotubesTransformer- electrical device

Carbon Nanotubes

• Carbon nanotubes (CNTs) are an interesting type of material due to its superior strength, and electrical conductivity.

4Shi, Z., Wang, Z., Gu, Z., Pristine and Filled Double-Walled Carbon Nanotubes(image) Guardian.co.uk

Carbon Nanotubes• Founded in 1991 by Sumio Lijima• Hollow cylinders made out of carbon atoms• 10,000 times smaller than a human hair

5http://www.gaia3d.co.uk/3d-models/3d-chemistry/carbon-nanotube/

Comparison

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My Hair CNTs Thread

10,000 times larger

Chemical Vapor Deposition (CVD)

• An irreversible deposition of a solid from a mixture of gases through a heterogeneous chemical reaction

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CNTs Thread

• CNTs thread gets spun up from a silicon wafer

• This process is like spinning cotton

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Densification

• The soaking of CNTs thread in solution containing water and acetone.

• This procedure helps improve the CNT thread by increasing the diameter of the thread and slightly increasing its strength.

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Chemical Doping

• A process of bonding electrons to the surface of the thread by disassociating an acidic solution.

– Nitric Acid– Sulfuric Acid

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SEM Pictures

11UC Nanoworld

Doped ThreadUn-doped Thread

The doped thread is 6.5x small in diameter than the undoped

Resistivity- Measurement of how a material opposes the flow of electrons.

•Lowers through doping

•Resistivity is inversely proportional to the diameter of the thread

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Doping Results

Material Average Resistivity (Ω m)

CNT (Nitric Acid) 1.12*10-5

CNT (Sulfuric Acid) 1.20*10-5

Copper 1.68*10-6

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Coating

• A process of covering the thread with a thin layer of insulated polymer

–Nylon–PVA–Nitrile

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Transformer

• What is it?

• How are we using it?

• Why are we using it?

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Source: eHow

Transformer

• Works on Faraday’s Law of induction

• Changes voltage and current levels

• Remains the same power

• Induced voltage vs. N(number of turns)

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N-NorthS-South

Source: WorldPress

What is it used for?

• Assists as voltage/current regulator

Within the project…

• Will prove properties of CNTs

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Final Product

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Source: Energy Efficiency

Power supply connected to primary coil

Light source connected to

secondary coil

CNTs threads will replace

insulated coils

Transformer

Transformer with the LED Bulb

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Transformer with CNTs

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Transformer with the LED

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Data

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CNT applications• CNTs Cable Wire

– Light weight– High temperature resistance– Durable

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Windsun.com

Conclusion

• Chemical Vapor Deposition is one way to make CNTs

• Lighter, and durable cables will incorporate CNTs

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Recommendations for Additional Research

• Add more windings

• Find the right inverter

• Try different type of doping solution

• Improve coating - PVA

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Acknowledgements

Dr. Vesselin Shanov

Dr. Noe Alvarez

Nicholas Kienzle

Brad Ruff

Doug Hurd

UC Nanoworld

NSF - Grant ID No.: DUE-075692126

Questions

?

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