Chemistry in Focus 3rd editionTro

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?