Nanotechnology

Nature of science:

Improvements in apparatus—high power electron microscopes have allowed for the study of positioning of atoms. (1.8)

The need to regard theories as uncertain—the role of trial and error in the development of nanotubes and their associated theories. (2.2)

“The principles of physics, as far as I can see, do not speak against the possibility of manoeuvring things atom by atom. It is not an attempt to violate any laws; it is something, in principle, that can be done; but in practice, it has not been done because we are too big.”

— Richard Feynman, Nobel Prize winner in Physics

• Molecular self-assembly is the bottom-up assembly of nanoparticles and can occur by selectively attaching molecules to specific surfaces. Self-assembly can also occur spontaneously in solution.
• Possible methods of producing nanotubes are arc discharge, chemical vapour deposition (CVD) and high pressure carbon monoxide (HIPCO).
• Arc discharge involves either vaporizing the surface of one of the carbon electrodes, or discharging an arc through metal electrodes submersed in a hydrocarbon solvent, which forms a small rod-shaped deposit on the anode.

Applications and skills:

• Distinguishing between physical and chemical techniques in manipulating atoms to form molecules.
• Description of the structure and properties of carbon nanotubes.
• Explanation of why an inert gas, and not oxygen, is necessary for CVD preparation of carbon nanotubes.
• Explanation of the production of carbon from hydrocarbon solvents in arc discharge by oxidation at the anode.
• Deduction of equations for the production of carbon atoms from HIPCO.
• Discussion of some implications and applications of nanotechnology.
• Explanation of why nanotubes are strong and good conductors of electricity.

• Some studies have shown that inhaling nanoparticle dust can be as harmful as asbestos. Should nanotechnology be regulated or will this hinder research?
• International collaboration in space exploration is growing. Would a carbon nanotube space elevator be feasible, or wanted? What are the implications?

Theory of knowledge:

• The use of the scanning tunnelling microscope has allowed us to “see” individual atoms, which was previously thought to be unattainable. How do these advances in technology change our view of what knowledge is attainable?
• Some people are concerned about the possible implication of nanotechnology. How do we evaluate the possible consequences of future developments in this area? Is the knowledge we need publicly available or do we rely on the authority of experts?

Utilization:

• Protein synthesis in cells is a form of nanotechnology with ribosomes acting as molecular assemblers.

Syllabus and cross-curricular links: Topics 4.3—molecular polarity

• Possible implications of nanotechnology include uncertainty as to toxicity levels on a nanoscale, unknown health risks with new materials, concern that human defence systems are not effective against particles on the nanoscale, responsibilities of the industries and governments involved in this research.
• Conductivity of graphene and fullerenes can be explained in terms of delocalization of electrons. An explanation based on hybridization is not required.

• Aims 1, 8 and 9: Investigate the theoretical and large scale manufacturing of nanotechnology products and their implications. Examples could include sporting equipment, medicinal products, construction, environmental cleaning, robotics, weaponry or other theoretical commercial uses.
• Aims 7, 8 and 9: Animations, simulations, and videos of nanotube manufacture and uses should be used.