Novel Dispersion and Self- Assembly of Carbon Nanotubes of Carbon - - PowerPoint PPT Presentation

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Novel Dispersion and Self- Assembly of Carbon Nanotubes of Carbon Nanotubes Mohammad F. Islam Department of Chemical Engineering and Department of Chemical Engineering and Department of Materials Science & Engineering 100g 100g

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SLIDE 1

Novel Dispersion and Self- Assembly

  • f Carbon Nanotubes
  • f Carbon Nanotubes

Mohammad F. Islam

Department of Chemical Engineering and

100g 100g

Department of Chemical Engineering and Department of Materials Science & Engineering http://islamgroup.cheme.cmu.edu

Korea-US NanoForum 2010, Seoul, Korea A il 5 6 2010 April 5-6, 2010

NSF: CBET- 0708418, DMR- 0619424 and DMR- 0645596 ACS PRF Funding Agencies ACS- PRF Sloan Foundation DARPA

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SLIDE 2

Outline Outline

I d i S f M i l

  • Introduction to Soft Materials
  • Single Wall Carbon Nanotubes (SWNTs)

g

  • Purification, Dispersions and Their Properties
  • Carbon Nanotube Aerogels
  • Carbon Nanotube Aerogels
  • Conclusions
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SLIDE 3

Soft Materials Soft Materials -

  • Introduction

Introduction

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SLIDE 4

Introduction to Single Wall Carbon Nanotubes Introduction to Single Wall Carbon Nanotubes

Diamond Diamond

C60 C60

“Buckminsterfullerene” “Buckminsterfullerene” Graphite Graphite Single wall Carbon Single wall Carbon Nanotube ( Nanotube (SWNT SWNT) Multiwall Carbon Multiwall Carbon Nanotube ( Nanotube (MWNT MWNT) )

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SLIDE 5

1

SWNTs have extraordinary anisotropic properties SWNTs have extraordinary anisotropic properties

~ 1 nm

100 nm – 10,000 nm

Strength (~100x Steel)

SWNT

Dekker et al., Nature 386, 474 (1997)

Electrical Conductivity (~Copper)

Tensile strength ~200 GPa Stiffness ~1 TPa Elongation ~30%

Salvetat et al., PRL 82, 944 (2000)

Thermal Conductivity ~3x Diamond

Incorporate anisotropic properties of SWNTs into composites

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SLIDE 6

Challenges Challenges

  • H

di i i l d h i l

  • Large scale production of clean nanotubes.
  • Homogeneous dispersion in solvents and host materials.

van der Waals attraction: 40 KBT/ nm

  • Control of diameter, chirality and length.
  • Determination of bulk properties and structural behavior.
  • Effective integration into composites.
  • Controlled integration into electronic circuits.
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SLIDE 7

Synthesis of SWNTs Synthesis of SWNTs

Research Experience for Undergraduates 2007 Hata et. al., Science 306, 1362 (2005)

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SLIDE 8

Purification of SWNTs Purification of SWNTs

Standard wet air burn with H2O2 Standard wet air burn with H2O2 Mild acid reflux Magnetic gradient fractionation Vacuum anneal

20 nm 20 nm Flow in nanotube

suspension Collect magnetically magnet

20 nm 20 nm

suspension magnetically fractionated nanotubes magnet

  • 3

2 3 Purification only 2 5 3.0

u/mg) x 10

1 2 Fractionated

nsity x 105

1 0 1.5 2.0 2.5

LMNT Purified LMNT puried and Fractionated HiPCO Purified HiPCO Purified and Fractionated

M (emu

  • 3
  • 2
  • 1

Inten

0.0 0.5 1.0

H (Tesla)

  • 12
  • 8
  • 4

4 8 12

wavenumber (cm-1)

500 1000 1500 2000

Nature Materials 4, 589 (2005)

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SLIDE 9

Surfactants Surfactants

Surfactant

+

Surfactant

H d hili h d

micelle

Hydrophobic tail Hydrophilic headgroup

water

water

  • il

+

water

Shake

+ +

water water

Oil droplets

+

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SLIDE 10

Dispersing SWNTs: Our Work Dispersing SWNTs: Our Work

Sodium Dodecyl Benzene Sulfonates (NaDDBS)

SDS Surfactant: TX 100 N DDBS

C12H25 SO3

  • Na+

3x10- 4 SWNTs: Time: SDS Surfactant: TX- 100 6x10- 4 5 days 5 days

2 months 2x10 - 2

NaDDBS

5.00 2.50 2.50 5.00 m

Nano Letters 3, 269 (2003)

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SLIDE 11

Purified and Suspended SWNTs Are Undamaged Purified and Suspended SWNTs Are Undamaged

Optical Properties

bance

0.3 0.4 0.5

sion

30 40 50

Absorb

0.1 0.2

Emiss

10 20

Wavelength (nm)

800 1200 1600 0.0

Electrical Properties

t (nA)

3 4 5 6

Metallic (x5)

p

Curren

1 2 3

Semiconducting (x10) Gate Voltage (V)

  • 10
  • 5

5 10

Nature Materials 4, 589 (2005)

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SLIDE 12

Aerogels Aerogels: Ultra : Ultra-

  • light

light M Mesoporous esoporous M Materials aterials

Ultra- light Highly porous materials Very high strength- to- weight Very high strength to weight Very high surface- area- to- volume ratio Ultra- light structural media Radiation detector Thermal insulator Battery electrode Supercapacitor Supercapacitor

Aerogel type Electrical Conductivity ( S/ cm ) Therm al Conductivity ( W / m -K) Density ( g/ cm 3) Conductivity ( S/ cm ) ( W / m K) Silica N/ A ~ 0.003 0.0019 ~ 0.1

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SLIDE 13

Rigidity Percolation Rigidity Percolation

Network formation Strong network

a) 105

at low  Strong network

s, G' (Pa 103 104 Modulus 102 ateau M 100 101 10-3 10-2 10-1 Pl 10-1 

  • Phys. Rev. Lett. 93, 168102 (2004)
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SLIDE 14

CNT CNT Aerogels Aerogels

Increasing CNT concentration

  • Phys. Rev. Lett. 93, 168102 (2004)

NanoLetters 6, 313 (2006)

CNT gels do not break apart

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SLIDE 15

CNT CNT Aerogels Aerogels

Density: 0.02 g/cm3

1 µm

Advanced Materials 19, 661 (2007)

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SLIDE 16

SWNT Aerogels SWNT Aerogels

100g weight on 3 aerogel posts

Total aerogel mass:

12.8 mg

100g 100g

12.8 mg 10 µm

Density 0.02 g/ cm3

100g 100g

Supports at least

~8,000x

  • wn weight

SWNT Aerogel posts

20 nm

  • wn weight

g p

Electrical Conductivity up to ~10 S/ cm Surface area 1860 m2/ g Thermal Conductivity ~0.3 W/ m- K

3 µm

Advanced Materials 19, 661 (2007)

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SLIDE 17

CNT CNT Aerogels Aerogels

1500

Current (mA)

750 0 8 0 4 0 4 0 8

  • 750
  • 0.8
  • 0.4

0.4 0.8

Voltage (V)

  • 1500
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SLIDE 18

Backfilling with Backfilling with epoxy epoxy

Epon 828 Resin + EpiKure 3234 Crosslinker Vacuum

Epoxy + cross linker

Aerogel

Vacuum removed

Resin “wicks” into sample

C d i i l l

  • Conductivity largely

unaffected by backfilling

  • Improved composite

conductivity

  • Adv. Mater. 17, 1186, 2005
  • Can be backfilled with

various substances

Fracture - Complete fill

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SLIDE 19

Fusing CNT Aerogel Fusing CNT Aerogel

PRL 89, 075505 (2002)

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SLIDE 20

Fusing CNT Aerogel Fusing CNT Aerogel

Nature Nanotech. 3, 17 (2008)

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SLIDE 21

Fusing Fusing CNT Aerogel CNT Aerogel

Irradiation gives rise to covalent bonds between the tubes. Th ll t th f th t b t i l i The overall strength of the nanotube materials may increase. Increase the tensile strength of macroscopic nanotube products. A beneficial effect on the electronic properties A beneficial effect on the electronic properties  Irradiation with moderate doses may increase the conductivity of nanotube networks.  Spatially localized irradiation can be used for creating functional  Spatially localized irradiation can be used for creating functional electronic nanotube- based devices.

Is it possible to fuse CNTs in 3D structure?

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SLIDE 22

Fused Fused CNT Aerogel CNT Aerogel

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SLIDE 23

Fused Fused CNT Aerogel CNT Aerogel

slide-24
SLIDE 24

Fused Fused CNT Aerogel CNT Aerogel

Defects on CNTs A fused CNT junction

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SLIDE 25

Fused Fused CNT Aerogel CNT Aerogel

7 8

HP Outside_hole holder_400V_annealing Outside_carbontape_200V_annealing

2 3 4 5 6

  • 2
  • 1

1 2

J (A/cm

2)

7

  • 6
  • 5
  • 4
  • 3
  • 5
  • 4
  • 3
  • 2
  • 1

1 2 3 4 5

  • 8
  • 7

Voltage (V)

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SLIDE 26

Conclusions Conclusions

W f b i t d lf bl d b t b b d lt li ht l

  • We

fabricated self- assembled carbon nanotube based ultra- light, large surface area- to- volume ratio electrically conducting porous structure – CNT aerogel.

  • CNTs can be fused at junction points to increase mechanical strength and

CNTs can be fused at junction points to increase mechanical strength and thermal properties.

100g 100g