Recently in Nanotechnology Category

Once again, Missouri S&T researchers are leading the way in nanomaterials.

Today, the journal Chemistry of Materials published online an article describing how Dr. Jay A. Switzer, the Professor of Discovery in S&T's chemistry department, and his team grew zinc nanoscale zinc oxide crystals on a single-crystal silicon (full article | press release).

The research on these little crystals -- Switzer calls them "nanospears" -- could yield big results for the future of solar energy. That's because both zinc oxide and silicon are semiconductors, and by perfectly aligning the two materials, engineers could create a new breed of solar cell that absorbs more of the solar spectrum, thereby increasing the efficiency of solar cells.

The other cool thing about Switzer's work in this area is that he's come up with an inexpensive way to grow zinc oxide on silicon. It's been done before -- but not on the cheap. Previously, researchers have had to use expensive ultra-high-vacuum methods. Switzer just uses a beaker and some alkaline solution -- and gets a better result.

Yue-Wern Huang's latest research involves creating a kind of Trojan Horse. But unlike the mythical gift from the Greeks or the more contemporary computer virus that bears the name, Huang's is designed to sneak good stuff into a bad place.

Huang, an associate professor of biological sciences at S&T, is building tiny vessels of cell-penetrating proteins that could possibly transport a cargo of quantum dots, along with proteins, medicine or DNA, into a malignant or otherwise infected cell and release the healing cargo -- medicine or some therapeutic agent of the future -- into the microscopic "Troy": the walled city of a cell.

The vessel -- Huang's Trojan Horse -- is a nontoxic protein transduction domain, or PTD,which is derived from a virus that can penetrate the cellular membrane.

This latest work is funded through a $225,000 grant from the National Institutes of Health under the American Recovery and Reinvestment Act.

By mimicking the interlocking structure of a bird's nest -- but on a much smaller scale, using nanoparticles -- Missouri S&T's Nicholas Leventis and his colleagues have come up with a way to make a certain class of aerogels less fragile. A recent edition of the journal Chemical Science reports:

Aerogels are typically made from pearl necklace-like strings of silica nanoparticles, and can be strengthened with a polymer coating, so that the strands form crosslinks wherever they meet. But inspired by the highly interlocked structures of bird nests, Leventis switched to vanadia-based structures, which form a more highly entangled worm-like nanostructure.

'Both crosslinked silica and vanadia are very strong materials. But crosslinked vanadia aerogels never fail under compression, and can absorb at least four times the kinetic energy of the silicon carbide ceramics used for armour,' said Leventis. 'Killer applications will be in areas where we can take advantage of the multifunctional character of these materials - strength in combination with acoustic and thermal insulation - such as lightweight structural materials for buildings, and the automotive and airplane industries.'

This is not the first time Leventis has gained notice for his work with nanomaterials. Last June, the chemistry professor made Nanotech Briefs' Nano 50 list of top researchers in the field. Leventis made the list for his previous work with aerogels.

That's how UMR chemist Nicholas Leventis describes his invention: cross-linked aerogels. The extremely lightweight and sturdy composite material is four to five times stronger than material currently used in military armor. This week he was named to Nanotech Briefs list of Nano 50 for his work.

Aerogels are nothing new. They've been around since the 1930s, but they were highly brittle and of little practical use. By chemically bonding -- or cross-linking -- strings of tiny glass particles with polymers like polystyrene, polyurethane and epoxy, Leventis created aerogels that are 100 times more resistant to breakage and totally resistant to moisture.

Leventis sees possible uses in military armor, lightweight thermal insulation, fuel transport systems, tiny, but sturdy, drug-delivery vehicles and lighter, more efficient aircraft and spacecraft frames.

Want to see something cool? These videos show the difference between conventional armor-grade material and a cross-linked areogel when they're hit with an impact that is eight times that of a .45 mm bullet. It's pretty impressive.

First, the conventional material:

Now, here's the aerogel:

Three-time UMR graduate James Friend has a big idea about a very small surgical device.

As reported today by Australian newspaper The Age, in Melbourne, Friend and his colleagues at Monash University are "developing micro-robots they hope will be able to swim through the human body and perform medical tasks." Friend hopes "to build a tiny machine no wider than two human hairs side by side to do the job."

Friend leads the Micro/Nanophysics Research Laboratory at Monash. He learned the art of designing minuscule motors at UMR, where he earned a bachelor's degree in aerospace engineering from UMR in 1992, then stayed on to earn his master's and Ph.D., both in mechanical engineering, in 1994 and 1998.

If I learned anything from reading Horton Hears a Who to my kids, it's that things as small as a speck of dust can be very important. Yangchaun "Chad" Xing's research proves it.

Xing has been working to develop an efficient polymer electrolyte membrane (or PEM) fuel cell using a new material called carbon nanotubes, which is more durable than carbon black (the traditional material used). Xing, assistant professor of chemical and biological engineering, along with Guoqiang Ren, a Ph.D. student at UMR, have developed a new, "fast evaporation" technique for depositing metal nanoparticles on carbon nanotubes. Their findings are in the November issue of the Institute of Physics Publishing journal, Nanotechnology.

National Geographic magazine takes a look at nanotechnology's big future this month. The magazine uses several comparisons to help put the size of the research into perspective. My favorite?

To put it another way, a nanometer is the amount a man's beard grows in the time it takes him to lift a razor to his face.

Via Sciencedude (here).

UMR physicists have developed a process to embed tiny particles of semiconducting materials into an ultra-lightweight material, called an aerogel. That in itself is pretty cool. But what's even cooler is that these quantum dots -- semiconducting specks only a few nanometers in diameter -- also emit and absorb light. At the same time.

Massimo Bertino, an associate professor of physics at UMR, is leading the team of researchers developing this method of embedding quantum dots into aerogel surfaces. Recently, Bertino demonstrated the method by embedding a miniature version of the UMR wordmark into an aerogel surface. The photo, taken by UMR graphic designer/photographer Ian Nance, shows how the dots emit light.

An international authority in the field of nano-materials, Jay Switzer has always been intrigued by experimentation and discovery. Even his title at UMR – he is the Donald L. Castleman/Foundation for Chemical Research Professor of Discovery – reflects his passion for the quest into the unknown. His specialty involves electrodeposition, a method of “growing" minuscule ceramic materials, layer by thin layer, on a base surface. It’s a process that mimics the way stalagmites grow from mineral deposits in caves.

Chuck Williams is always seeking attention.