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Chemistry in Focus 3rd edition Tro

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Chemistry in Focus 3rd edition Tro Powered By Docstoc
					Chemistry in Focus 3rd edition
             Tro




       Chapter 19
     Nanotechnology
       Out of SciFi; Into the Lab
• Five atoms, end to end, measure a nanometer (10-9
  m).
• Human hair measures 20,000 nm in diameter.
• Can we make a machine so tiny is could navigate the
  bloodstream?
• Nature has already done this.
• Some see nanotechnology as bioimitation.
Scanning Tunneling Microscope
• 1981 Binnig and Rohrer measuring
  electrical conductivity over a surface
• Noticed bumps in their measurements
  which have been interpreted as individual
  atoms
• Modern STMs scan surfaces of interest
  with atomically fine metallic tips.
• We can not only image atoms, but move
  them
           Atomic Visibility
• STM made the atomic world visible for the
  first time.
• Premier tool for scientists developing
  nanotechnology
• Binnig and Rohrer were awarded the 1986
  Nobel Prize in physics for this work.
        Atomic Force Microscope
• STM can image only metallic surfaces
• AFM (atomic force microscopy) can image nonmetallic
  surfaces
• AFM tracks the movement of a laser reflected off the
  back of a cantilever
• Tapping AFM can image biological samples
               Buckyballs
• Graphite – carbon atoms in layered sheets
• Diamond – three-dimensional honeycomb
• Buckyballs – 60 carbon atoms bonded into
  a hollow sphere
  – Smalley, Curl, Kroto awarded the 1996 Nobel
    Prize in chemistry
  – Named for R. Buckminster Fuller, American
    architect of geodesic designs resembling C60
                 Nanotubes
• 1991 marks the birth of the buckytube
  – Shape is tubular instead of spherical




• A few atoms in diameter but kilometers in
  length
  – Strong as steel
  – Can be made electrically conducting
Weighing and Writing with Atoms
      Conducting Electricity with
            Nanotubes
• Tiny electric circuits may allow
  – Flat-panel displays
  – Water desalination
  – Flexible, foldable monitor displays
             Nanomedicine




• Doctors can encase foreign cells so that
  the body will not reject them.
  – Pancreatic animal cells can be introduced into
    a human diabetic patient.
 Artificial Cells and Nanorobots
• Can we construct nanomachines that
  mimic living cells?
• Can we construct nanorobots that can do
  work within biological systems?
• Current work involves targeted drug
  delivery
  – Protection of healthy cells from chemo drugs
  – Concentrated delivery of toxins to cancerous
    tissue
            Nanoproblems


• Can nanotechnology visionaries go to far?

• How will the ethics of such power be
  handled?

				
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posted:4/30/2014
language:English
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