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URMA URMA

ENORMOUS POTENTIAL FOR SHRINKING TECHNOLOGY

by Suzanna Engman


Nanotechnology defined

Nanotechnology may soon change every aspect of our lives, say researchers, and the University of Puerto Rico, Río Piedras is one of an increasing number of research facilities investigating its possibilities.

With nanotechnology, computers could store trillions of bytes of information in a structure the size of a sugar cube. Patients could drink fluids filled with nanorobots that are programmed to attack cancer cells and viruses. Manufacturing facilities could create less pollution while becoming less dependent on non-renewable resources, and manufactured goods of all kinds could be produced efficiently and inexpensively. If predictions prove true, we could reap some of the benefits of nanotechnology within 15 years.

Nanoscience, the basis of nanotechnology, combines the research of physics, chemistry, engineering, biology, mathematics, and computer science to build and study structures measured in nanometers. A nanometer (derived from the Greek word "nanos" for midget) is a billionth of a meter, or a millionth of a millimeter. To put a single nanometer into perspective, "the diameter of a human hair is around ten thousand nanometers and, therefore, huge by comparison," says Gerardo Morell, Ph.D., a chemical physicist and one of the nanoscience researchers at UPR, RP.

"We're talking about a degree of miniaturization never thought of before. You can't even see these objects with an optical microscope. They're smaller than a virus."

The Center for Nanoscale Materials

In order to develop and better see the results of their nanoscale experiments, ten UPR scientists from a variety of disciplines collaborated on a NASA proposal to create the Center for Nanoscale Materials and purchase, among other necessary items, a $700 thousand state-of-the-art Transmission Electron Microscope. The TEM, explains Carlos Cabrera, Ph.D., chemistry, and principal investigator of the CNM, will be the only microscope of this caliber on the island. It is scheduled to arrive in late Spring 2004.

Altogether NASA provided the CNM with $6 million over five years to investigate nanoscience. Included in the NASA University Research Center Grant is money for 11 undergraduate student researchers, 11 graduate student researchers, and three post-doctorate positions. The University also funds the CNM with in-kind funding. But don't look for a new building named CNM on campus. The CNM is "a virtual center," says Morell, made up of ten individual laboratories scattered across the Campus.

The CNM includes three clusters of nanoscience investigation. The Energy Storage Cluster investigates ways to create higher energy density storage (more energy with less weight). This research may someday make it possible for space shuttles to travel farther distances without needing to refuel.

In the Display Materials Cluster, UPR scientists are growing nanodiamonds, not for their sparkle, but for their extraordinary durability. Because diamonds are one of the hardest substances known, they can withstand the high radiation of the typical space environment and will not break down as easily as silicon cells, which degrade after only a few years in orbit.

The nanodiamonds being studied at the CNM also have consumer applications. The Display Materials Lab investigates how to make electronic materials stronger using nanodiamond film, in order to manufacture more robust electronic devices that are resistant to radiation, shock, and extremes of temperature. Right now, says Morell, electronic products are very vulnerable. For example, computers need to be kept in climate-controlled rooms in order to function properly. If they were made with nanodiamonds rather than silicon, they would be more reliable, less fragile, and last longer.

Nanodiamond technology also has implications for national defense, as well as for biomedical science. One UPR, RP neuroembryologist, Eduardo Rosa–Molinar, Ph.D., uses fluorescent diamond nanoparticles in his studies of neurodevelopment. Rosa-Molinar and Adaris Rodríguez-Cortés, an undergraduate student in his laboratory, manipulate them as visualization probes in living embryonic and adult cells. They help the researchers detect the origin and the movements that lead to cellular specialization and maturation of living cells in the central nervous system.

Iris Mónica Vargas, graduate student in physics, checks the nanodiamond deposition process in the Chemical Vapor Deposition System, an instrument made by students in the CNM laboratory. (Photo: José Pérez Mesa)

The third cluster of CNM, the Fuel Cells Cluster, investigates the means to create more environmentally friendly and efficient fuel cells (batteries) that will, for example, provide enough power to drive a car for days without refueling. The fuel cells we now use slowly lose efficiency until they no longer work, and they destroy the environment. So researchers are working on ways to develop hydrogen fuel cells. Hydrogen is readily available, and because the only byproduct of hydrogen fuel is water vapor, hydrogen fuel cells don't harm the environment. Soon we may have clean-burning fuels without reliance on petroleum products.

Nanotechnology is an emerging multidisciplinary field, drawing from physics, mathematics, chemistry, biology, and engineering. In the past, for convenience, universities divided branches of knowledge into discrete sciences, but nature never did. And because nanotechnology imitates what happens in nature, academic disciplines can no longer work separately. In order to meet the challenges of nanotechnology, the disciplines will need to work together, as they are doing at the CNM.

Inside a CNM laboratory

If you walk into the Display Materials Laboratory in the Facundo Bueso building, you'll see that three large instruments dominate the apparatus-packed room. The instrument to grow diamonds looks like a primitive underwater helmet, similar to Captain Nemo's in 20,000 Leagues Under the Sea, except it has three viewing portals instead of one. It's called the Chemical Vapor Deposition System, and, as Morell explains: "It's homemade. We saved money and incorporated design and testing into the academic experience of students." Morell estimates that he and his students were able to make it for about $150,000, half of the prefabricated cost.

Gerardo Morell taking electron field measurements with the Electron Field Emission Setup instrument in the CNM laboratory.
(Photo: José González Peniza)

Another homemade instrument, the Electron Field Emission Setup, measures the electrical properties of diamond films grown in the CVD, in order to determine the strength of the materials. "We need robust electronic materials. What we have is too fragile. Suppose an airplane's electronic devices fail? What about national security? These are instances in which we must have robust electronic devices."

Silicon, Morell points out, has reached its capacity for miniaturization. "We want to replace silicon. Now computers become obsolete. They're sent to the dump, which becomes a huge problem. We need more environmentally friendly materials," Morell says.

The third instrument, the Arc Discharge Deposition System, referred to as "the birdcage," looks like a large upside down glass jar surrounded by a removable metal cage. The birdcage produces a small fireworks display as it manufactures nanotubes, making it necessary for researchers to wear helmets with protective visors. Nanotubes are the building blocks for nanoelectronics. "They are the interconnecting parts of nanodevices. Instead of having silicon wafers, eventually we will have just nanotubes," Morell explains. "The nanotubes are the nuts and bolts of nanomachines."

To demonstrate how nanotubes are made, physics graduate research assistant Joel de Jesús fills the birdcage with nitrogen gas, inserts carbon rods filled with boron into the chamber, and turns on the voltage. The birdcage lights up like a 4th of July sparkler, only 100 times brighter.

Although the exact temperature of the spark is unknown, it exceeds 3,000 degrees Celsius, says de Jesús. "We tried to take the temperature once, but it destroyed the thermometer."

The spark causes nanotubes to be formed. "For reasons not yet understood, the graphite, when heated, creates amorphous carbon (carbon powder) and boron nitride nanotubes," says de Jesús.

Nestled in the carbon powder, the nanotubes can only be seen with an electron microcope–with the naked eye they look like worthless soot. Their potential value, however, is priceless.

Carbon nanotube, visible only by means of electron microscope, is a new form of carbon measuring a few nanometers in diameter and several microns long. Nanotubes are the building blocks for nanoelectronics devices, circuits, and computers.

Illustration courtesy of NASA Ames Center for Nanotechnology

Although the exact temperature of the spark is unknown, it exceeds 3,000 degrees Celsius, says de Jesús. "We tried to take the temperature once, but it destroyed the thermometer."

The spark causes nanotubes to be formed. "For reasons not yet understood, the graphite, when heated, creates amorphous carbon (carbon powder) and boron nitride nanotubes," says de Jesús.

Nestled in the carbon powder, the nanotubes can only be seen with an electron microcope–with the naked eye they look like worthless soot. Their potential value, however, is priceless.

Nanotechnology obstacles

The goal of nanotechnology is to manipulate nanomaterials such as nanotubes and place them in a pattern to produce a structure or product. In order to produce nanoproducts, the first problem to solve is how to manipulate the nanomaterials. How do technicians move, with precision, something so tiny that you can't even see it with an optical microscope, much less the unaided eye? It's like trying to snap together legos wearing boxing gloves, states an article on nanotechnology. A second problem is creating nanoscopic machines, or assemblers, to manipulate the nanomaterials. Once this is accomplished, there is the problem of creating enough assemblers to mass produce nanoscale products. These three difficulties pose considerable challenges to nanotechnology.

"Science is just beginning to learn how to directly manipulate objects at the atomic level, but we'll soon be entering the Nanotechnology Era. Those of us who grew up during the Semiconductor Era and enjoy many technological advances, such as computers, Internet, and cellular phones, will look back upon this time with the same feelings that we have today toward medieval times, when technology was more primitive," says Morell.

Researchers all over the world are racing to develop nanotechnology, and those who get there first will have a great economic advantage. Because nanotechnology has the potential to advance medicine, preserve the environment, and eliminate poverty, Morell believes that nanotechnology knowledge should be shared. "Ethical issues such as the need to share knowledge and technology will become crucial for the preservation of humankind," says Morell.

http://web.uprr.pr/diamond

   
     
 

 

 

 

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