Publications

WINS Distinguished Lecturer :
Dr. Franz J. Himpsel

"Nanoscience by the ton"

 

Dr. Franz Himpsel

Nanotechnology Research Grows Beyond the Beaker

By Mitchell Zimmer

The field of nanotechnology is developing very quickly, so much so that the Western Institute for Nanomaterials Science (WINS) held its second annual one day workshop on March 24 to highlight both the experimental and theoretical research activities that take place here at Western. Nanoscience at Western is an interdisciplinary effort, involving the Faculties of Science and Engineering Science and various research centers on and off campus. The one day workshop welcomed guest speakers Dr. Franz Himpsel of the Physics Department at the University of Wisconsin and Dr. Gianluigi Botton from the Brockhouse Institute for Materials Research at McMaster University. In order to get a grasp of the scale this technology, just keep in mind that one nanometer (nm) is one millionth of a millimeter. To put it another way, the width of a double helix DNA molecule is roughly two nanometers.

Western Institute for Nanomaterials ScienceThe significance of many biological materials existing in the nanoscale is not lost on today’s researchers who are now incorporating these structures within their experiments. As Dr. Himpsel noted in his public address on March 23 as WINS Distinguished Lecturer, past researchers were assembling “nanocrystals or nanotubes, things like that in a beaker- which was mostly chemistry oriented- but then they found out that they could attach organic biomolecules to that, so nanotechnology became nano plus bio. Now I think that when you write a proposal you should have nano plus bio plus info to be successful. Some of the info part that I find interesting is when you look at what kind of information content is in biomaterials. I was kind of stunned to hear that the part of DNA that codes for protein is only 100 megabytes or less. I’ve seen Powerpoint presentations that are 100 megabytes.” Another branch of nanotechnology concerns how the molecular components come together to form structures. “How do you wire all these things up into some useful devices,” Hempsil asked, “even if you could self assemble a whole transistor, how do connect the transistors into some logic circuit or some memory?” He added, “That usually won’t work by spontaneous self-assembly.”

In spite of these difficulties, nanotechnology is not an esoteric field of study where the benefits are years away. “Nanotechnology has already penetrated our daily lives, it’s just not called that way,” says Hempsil. There are now start-up companies that sell nanocrystals and nanotubes. There is also a case where you have, as Hempsil says, “nanoscience by the ton.” Non-fading iridescent car paint is now available where the colour is a product of the interference patterns produced by thin half micron sized mica flakes each coated with 10 nm of titanium dioxide, a substance with a high refractive index. As a result, the paint actually contains no dye so the colour is not susceptible to bleaching by the sun’s heat or intense light.

The remainder of Hempsil’s talk focused along the lines of the high-tech applications. Working in the nanoscale presents some unique challenges, there is the opportunity to develop quantum well lasers to an optimum band gap of 6 nm which could improve the efficiency of working with optical storage media. When it comes magnetic hard drives there is the size limit of having the magnetic grains no smaller than 10 nm or else the magnetic signal decays. Yet improvements can be made to the recording head and the storage media by working down to the level of molecular monolayers. In the case of magnetic storage media, the addition of a three atom thick sublayer of Ruthenium and aligning the magnetic layer to allow a process called perpendicular recording would enable this new type of disc to store 312 gigabytes per square inch. That’s a sizable increase from the 40 gigabyte hard disks commonly used today.

Himpsel also considered studies of biological molecules which are already in the nanoscale and how they worked. The molecules actin and myosin work in conjunction to make muscle fibers contract. Hempsil presented an animation of how a single myosin molecule is chemically powered by a substance called ATP to move along the actin fiber. Hempsil also showed X-ray absorption studies of single stranded DNA to analyze their structure.