July 29, 2007
Thin Nanosheet Strong As Plexiglass
Fun with nanotechnology.
Tightly packed molecules lend unexpected strength to nanothin sheet of material
Scientists at the University of Chicago and Argonne National Laboratory have discovered the surprising strength of a sheet of nanoparticles that measures just 50 atoms in thickness.
“It’s an amazing little marvel,” said Heinrich Jaeger, Professor in Physics at the University of Chicago. “This is not a very fragile layer, but rather a robust, resilient membrane.”
Even when suspended over a tiny hole and poked with an ultrafine tip, the membrane boasts the equivalent strength of an ultrathin sheet of plexiglass that maintains its structural integrity at relatively high temperatures.
“When we first realized that they can be suspended freely in air, it truly surprised all of us,” said Xiao-Min Lin, a physicist at Argonne’s Center for Nanoscale Materials.
They used gold particles separated by organic (probably meaning carbon-based) nanoparticles.
The experimental material consisted of gold particles separated by organic “bumpers” to keep them from coming into direct contact. The research team suspended this array of nanoparticles in a solution, then spread the solution across a small chip of silicon, a popular semiconductor material. When the solution dried, it left behind a blanket of nanoparticles that drape themselves over holes in the chip, each hole measuring hundreds of nanoparticles in diameter. Then the researchers probed the strength of the freely suspended nanoparticle layer by poking it with the tip of an atomic force microscope.
The research team also found that the material held together when heated until reaching temperatures of 210 degrees and beyond.
What I wonder: Will nanomaterials made from more plentiful elements perform just as well at many tasks as rarer elements which we will run out of? How much will nanotech allow us to develop substitutes for rarer elements? Once we develop renewable substitutes for fossil fuels will we suffer shortages of anything besides land?
How much of the current run up in the gold price due to inflationary monetary policies or more and more demand for gold to make nanomaterials and devices?
At this point the use of gold for nanomaterials is mostly for experimental purposes. So the total gold used for this is very small.
Iron replaces platinum in fuel cells:
"In conventional hydrogen fuel cells the rapid interconversion of protons and electrons to hydrogen requires catalysis by expensive metals, usually platinum. In the living world enzymes catalyse this same reaction at extraordinary rates using abundant metals. Tard et al. now report the chemical synthesis of the iron–sulphur structure at the heart of the hydrogenase protein. The resulting iron–sulphur framework functions as an electrocatalyst for proton reduction, a potentially important step towards new materials to replace platinum in the anodes of fuel cells."
To answer your questions twice:
2. It doesn't matter for the conceivable future. Low cost access to space will mean (1) access to the metal deposits in the asteroid belt, which at today's consumption rates are virtually unlimited, and (2) lots more real estate.
I agree that the answer to #1 is "yes," with the possible exception of really heavy metals and such.
I think the answer to #2 is yes, as well, particularly if you include water in your definition of "land." We can already see where nano technology is going to render power-issues moot within 50 to 100 years. Nano-wired lighting, television, computers, etc. are coming first, and will dramatically decrease the amount of power every human requires to do what we do best: sit and surf the web, or watch TV. Nano-wired motors on your Air Conditioner, clothes/dish washers, and automobiles will also yield significant power reductions, but there are rules of physics that can't be denied. A compressor still requires a lot of juice to crush R12 back into a liquid; a 1,000Kg automobile still requires a lot of power to move it. As aggressive as nano-technology is in reducing power requirements for home lighting and electronics (a large % of overall use), they will be less effective in electro-mechanical situation.
Still, the news is good. Concurrent with home power requirements falling by upwards of 70%, we'll be seeing home power generation technologies like solar, wind, etc. becoming much more effecient through the same nano technologies.
In other words, power shouldn't be a problem in about 100 years.
Land and water are tougher nuts to crack - particularly industrial and agricultural water. Maybe some of the genetic engineers can develop desert-friendly wheat. I hope so, because once the Oglala and other similar aquifers are tapped out, you're going to see more desertification than you thought possible.
And de-salinization is extremely energy or land intense. I'm not sure that energy efficient de-salinization techniques will be ready when we need them...