Joined: 16 Mar 2004
|Posted: Mon Aug 31, 2009 9:49 am Post subject: Nanobama – The Making of a President
|University of Michigan professor John Hart has been analysing what makes a president - using nanotechnology; taking carbon nanotubes, he has imaged them using a scanning electron microscope.
Nanobama: Each face is made of approximately 150 million vertically aligned
carbon nanotubes grown by high temperature chemical reaction
The nanobama structures are made of carbon nanotubes, and the pictures were taken using optical and electron microscopes. Carbon nanotubes (CNTs) are tiny hollow cylinders of carbon; the diameter of a CNT is tens of thousands of times smaller than a human hair, and CNTs are several times stronger and stiffer than steel. CNTs are grown by a high-temperature chemical reaction, using patterns of nanoscale metal catalyst particles arranged in the shapes of the faces, text, and flags that you see in the images. Each face contains millions of parallel nanotubes, standing vertically on the substrate like a forest of trees. If you were standing next to the nanotubes as they grow, and each nanotube was a 1 foot (0.3 meter) diameter tree, the trees would be growing at over 500 miles per hour! The nanobama faces are approximately 0.5 millimeter wide, or about ten times the width of a human hair.
The nanobamas are made as follows, and as shown in the diagram below:*
(1) convert a cartoon of Barack Obama to a line drawing
(2) shrink the drawing and print it onto a glass plate (mask), using a laser system
(3) shine ultraviolet light through the mask, and onto a thin layer of polymer on a silicon wafer, thereby patterning the polymer by photolithography
(4) coat the wafer with a thin layer of catalyst nanoparticle "seeds" for nanotube growth
(5) remove the remaining polymer, leaving the catalyst seeds in the shapes of the nanobamas
(6) grow the CNTs from the catalyst patterns, by placing the wafer in a high-temperature furnace and filling the furnace with a carbon-containing gas
(7) take pictures of the structures, which are barely visible to the naked eye, using electron and optical microscopes
More seriously, carbon nanotubes and other nanostructures are building blocks for many important technological advances, including high-performance solar cells and batteries, new methods of diagnosing and treating disease, next-generation computer processors and memory, and lightweight composite materials. Broad awareness and understanding of the widespread benefits, implications, and potential risks of nanotechnology will be essential for its commercial success. Likewise, public and private support for research and education programs catalyzes economic growth and enable continued breakthroughs in energy, medicine, communications, and other vital areas.
* There are no instructions for a John McCain.