American Chemical Society Regional Meeting - 66th SWRM/62nd SERMACS

New Orleans, LA

November 30 - December 4, 2010

Barron Group Abstracts

"Synthesis and characterization of dielectric coated Si and Ge QDs"

Brittany L. Oliva and Andrew R. Barron

Hydrophilic silicon and germanium quantum dots were synthesized by a "bottom-up" method utilizing micelles to control particle size. Liquid phase deposition of silica on these quantum dots was successful using DTAB (dodecyltrimethylammonium bromide) as a surfactant to yield uniform spheres. The silica coated quantum dots were then arrayed in three dimensions using a slow drying technique on quartz slides. UV-vis absorbance and AFM and TEM images were used to analyze the particles at every stage.

"Ensemble characterization of carbon nanotube growth from various metal catalysts"

Andrew C. Owens, Alvin W. Orbaek, and Andrew R. Barron

The catalytic growth of Vertically Aligned Single Walled Carbon Nanotubes (VA-SWNTs) was acheived using a variety of metal oxide nanoparticles. The growth of nanotubes from iron oxide nanoparticles were compared with bi-metallic nanoparticles made from the main group transition metal series: manganese, cobalt, nickel and copper that were incorporated into the iron oxide matrix. VA-SWNTs were confirmed by Scanning Electron Microscopy, and then probed by Raman Spectroscopy. Analysis of the Raman spectra, particularly of the Radial Breathing Modes (RBM) show that the metal composition could be responsible for diameter selective growth of nanotubes. Radial Breathing Mode peaks were shown to vary according to the metal in the nanoparticle catalyst suggesting that metals in the catalyst produced nanotubes of specific diameter. As such, diameter and chirality controlled growth could eventually be controlled based on the catalyst particle chemistry. Chirality controlled growth of SWNTs is one of the last remaining stumbling blocks to its large scale use.

"Amplification of single walled carbon nanotubes as a route to achieving the armchair quantum wire"

Alvin W. Orbaek, Andrew C. Owens, Andrew R. Barron

Possibly the last remaining stumbling block to the use of single walled carbon nanotubes (SWNTs) in electronic devices, comes from a lack of synthetic control. When they are produced the material can exhibit properties ranging from metallic, to semiconducting. But this could be overcome when purified single chirality tubes are amplified in length, and also en mass. Using this technique one can increase the amount of an armchair nanotube, such that a macro scale device such an as armchair quantum wire could be made. The amplification of nanotube populations was achieved by selection of adequate partial pressures of methane and hydrogen. The rate of amplification was found to be 10% under the appropriate conditions. Investigation of the affect due to temperature yielded a higher efficiency of 15%. This work demonstrates equilibrium conditions of nanotube synthesis based on the decomposition of a hydrocarbon gas and the subsequent formation of nanotubes.

"Teaching the scientific process with silver nanotechnology"

Alvin W. Orbaek, Andrew R. Barron

High school students were taught to make silver nanoparticles with varying properties. They then used their own material to conduct research in biology, chemistry and physics. Conducting research engenders the very essence of the scientific process. The scientific process is based on empirical investigation, logical argument, and deductive reasoning. By involving students in the process of research they are exposed to the scientific process on a personal level, and they learn to tackle the research question at hand, using the scientific process as their guide. As a result of their work they then come to learn something about the physical world, because they gain some scientific insight from their investigations. The chemistry facts become trivial to learn, because they can now see for themselves the truth in the chemistry fact as they have come to this truth by themselves. For this reason they could learn a great deal about a variety of fields they might otherwise not have learned at their level.