TOPICS IN (NANO) BIOTECHNOLOGY
This presentation is the property of its rightful owner.
Sponsored Links
1 / 23

TOPICS IN (NANO) BIOTECHNOLOGY Carbon nanotubes PowerPoint PPT Presentation


  • 98 Views
  • Uploaded on
  • Presentation posted in: General

TOPICS IN (NANO) BIOTECHNOLOGY Carbon nanotubes. 10th June 2003. Carbon nanotubes. Overview. Introduction Synthesis & Purification Overview of applications Single nanotube measurements Energy storage Molecular electronics Conclusion and future outlook. Introduction: common facts.

Download Presentation

TOPICS IN (NANO) BIOTECHNOLOGY Carbon nanotubes

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Topics in nano biotechnology carbon nanotubes

TOPICS IN (NANO) BIOTECHNOLOGY

Carbon nanotubes

10th June 2003


Topics in nano biotechnology carbon nanotubes

Carbon nanotubes


Overview

Overview

  • Introduction

  • Synthesis & Purification

  • Overview of applications

  • Single nanotube measurements

  • Energy storage

  • Molecular electronics

  • Conclusion and future outlook


Introduction common facts

Introduction: common facts

  • Discovered in 1991 by Iijima

  • Unique material properties

  • Nearly one-dimensional structures

  • Single- and multi-walled


Topics in nano biotechnology carbon nanotubes

Definition

Single-wall carbon nanotubes are a new form of carbon made by rolling up a single graphite sheet to a narrow but long tube closed at both sides by fullerene-like end caps..

However, their attraction lies not only in the beauty of their molecular structures: through intentional alteration of their physical and chemical properties fullerenes exhibit an extremely wide range of interesting and potentially useful properties.


Topics in nano biotechnology carbon nanotubes

History

  • 1991 Discovery of multi-wall carbon nanotubes

  • 1992 Conductivity of carbon nanotubes

  • 1993 Structural rigidity of carbon nanotubes

  • 1993 Synthesis of single-wall nanotubes

  • 1995 Nanotubes as field emitters

  • 1997 Hydrogen storage in nanotubes

  • 1998 Synthesis of nanotube peapods

  • 2000 Thermal conductivity of nanotubes

  • 2001 Integration of carbon nanotubes for logic circuits

  • 2001 Intrinsic superconductivity of carbon nanotubes


Nanotube structure

Nanotube structure

  • Armchair structure

  • Zigzag structure

  • Chiral structure

  • Defects result in bends and transitions

    • Roll a graphene sheet in a certain direction:


    Special properties

    Special properties

    • Difference in chemical reactivity for end caps and side wall

    • High mechanical strength

    • Special electrical properties:

      • Metallic

      • Semi conducting


    Topics in nano biotechnology carbon nanotubes

    Special properties

    • Metallic conductivity(e.g. the salts A3C60 (A=alkali metals))

    • Superconductivitywith Tc's of up to 33K (e.g. the salts A3C60 (A=alkali metals))

    • Ferromagnetism(in (TDAE)C60 - without the presence of d-electrons)

    • Non-linear optical activity

    • Polymerizationto form a variety of 1-, 2-, and 3D polymer structures


    Topics in nano biotechnology carbon nanotubes

    Special properties

    • Nanotubes can be either electrically conductive or semiconductive, depending on their helicity.

    • These one-dimensional fibers exhibit electrical conductivity as high as copper, thermal conductivity as high as diamond,

    • Strength 100 times greater than steel at one sixth the weight, and high strain to failure.


    Topics in nano biotechnology carbon nanotubes

    Current Applications

    • Carbon Nano-tubes are extending the ability to fabricate devices such as:

    • Molecular probes

    • Pipes

    • Wires

    • Bearings

    • Springs

    • Gears

    • Pumps


    Topics in nano biotechnology carbon nanotubes

    Synthesis: overview

    • Commonly applied techniques:

      • Chemical Vapor Deposition (CVD)

      • Arc-Discharge

      • Laser ablation

    • Techniques differ in:

      • Type of nanotubes (SWNT / MWNT / Aligned)

      • Catalyst used

      • Yield

      • Purity


    Synthesis growth mechanism

    Synthesis: growth mechanism

    • Metal catalyst

    • Tip growth / extrusion growth


    Synthesis cvd

    Synthesis: CVD

    • Gas phase deposition

    • Large scale possible

    • Relatively cheap

    • SWNTs / MWNTs

    • Aligned nanotubes

    • Patterned substrates


    Synthesis arc discharge

    Synthesis: Arc Discharge

    • It was first made popular by Ebbessen and Ajayan in 1992

    • It is still considered as one of the best methods for producing carbon nanotubes other than CVD

    • In order to produce a good yield of high quality nanotubes, the pressure, consistent current, and efficient cooling of the electrodes are very important operating parameters


    Synthesis arc discharge1

    Synthesis: arc discharge

    • Relatively cheap

    • Many side-products

    • MWNTs and SWNTs

    • Batch process


    Topics in nano biotechnology carbon nanotubes

    Synthesis: arc discharge


    Synthesis laser ablation

    Synthesis: laser ablation

    • Catalyst / no catalyst

    • MWNTs / SWNTs

    • Yield <70%

    • Use of very strong laser

    • Expensive (energy costs)

    • Commonly applied


    Purification

    Purification

    • Contaminants:

      • Catalyst particles

      • Carbon clusters

      • Smaller fullerenes: C60 / C70

    • Impossibilities:

      • Completely retain nanotube structure

      • Single-step purification

    • Only possible on very small scale:

      • Isolation of either semi-conducting SWNTs


    Purification1

    Purification

    • Removal of catalyst:

      • Acidic treatment (+ sonication)

      • Thermal oxidation

      • Magnetic separation (Fe)

    • Removal of small fullerenes

      • Micro filtration

      • Extraction with CS2

    • Removal of other carbonaceous impurities

      • Thermal oxidation

      • Selective functionalisation of nanotubes

      • Annealing


    Potential applications

    Potential applications

    • < AFM Tip

    • > Molecular electronics

      • Transistor

    • > FED devices:

      • Displays

    • < Others

    • Composites

    • Biomedical

    • Catalyst support

    • Conductive materials

    • ???

    • < Energy storage:

      • Li-intercalation

      • Hydrogen storage

      • Supercaps


    Conclusions

    Conclusions

    • Mass production is nowadays too expensive

    • Many different techniques can be applied for investigation

    • Large scale purification is possible

    • FEDs and CNTFETs have proven to work and are understood

    • Positioning of molecular electronics is difficult

    • Energy storage is still doubtful, fundamental investigations are needed


    Topics in nano biotechnology carbon nanotubes

    Homework

    • Find an article from 2003-2004 describing a biological application of carbon nanotubes and make a short summary to explain to the rest of the class next week.


  • Login