nanotube synthesis success

Last Monday in my post I mentioned that I was trying to complete synthesis of a nanotube array on my own. I have, indeed, accomplished this task but it took me a few days to achieve success because as every scientist knows you must usually try many times before you get what you hope for. In my case, it took three tries, so I guess the cliché “three time’s the charm” held true for me. Both of my first two attempts to create a nanotube array ran into error with the last step of the procedure involving the furnace, which uses methane and hydrogen gas to grow nanotubes from the deposited FeO3 catalyst on the surface of silicon wafers. The first time in the middle of the experiment the furnace ran out of hydrogen gas, while the second time was even more frustrating because a grad student accidentally pressed the wrong button on the circuit breaker that powered the furnace and subsequently turned it off during my experiment. However, when I finally achieved construction of a single walled nanotube array (SWNT) with my third attempt, it made my success feel much more worthwhile.

Recently, instead of doing SWNT synthesis I have been given the project to make multi-walled nanotubes (MWNTs), since we want to see if we can cut these nanotubes with our photocatalyst. If this is possible, it will have great implications for nanotube devices in the future if such cutting can be done on a large-scale. Surprisingly, MWNTs are much easier to make than SWNT since some of the preliminary steps can be taken out, such as exposing the silicon wafers to the piranha solution; this is because with MWNTs it is not as important for the silicon dioxide surface to be protonated by this highly acidic solution. The only preliminary steps that need to be done with the wafers are to expose them to acetone in a water-bath for 10 minutes, then in ethanol for 10 minutes. The rest of the procedure is carried out in the furnace. I was very fortunate to get one of the grad students familiar with MWNTs to walk me through how the engineering dynamics of the furnace work, which actually is a very simple process. In contrast to SWNT, the carbon source for MWNT synthesis is held in a cylinder at the bottom of the furnace as opposed to the methane gas flow, which serves as the carbon source in SWNT synthesis. Therefore, Argon gas is used to carry the carbon source in the furnace to the quartz tube where the reaction happens. The grad student who helped me with this was named Yongyi Zhang and he will be going to U of M this coming fall for a Post Doc position in the Mechanical Engineering Department. Other students in the lab told me before that Yongyi is sort of the engineering genius in the lab, where if something breaks he’s the one to fix it. I had no question about this statement after we worked together. For example, he fixed a small electrical device, which we needed to heat up the iron cyclohexane catalyst in the quartz tube, by detaching, reattaching, and splicing wires together. I do believe he might become a great professor at U of M in the near future because of his engineering expertise and his ability to teach others---in this sense U of M is very lucky to have him. In the last few days Yongyi has been looking online for housing at U of M, which I have tried to help him with; however, this is no small task since much of the housing close to North Campus is already taken and it is very difficult to make any arrangements with landlords when you’re not in Ann Arbor. I know I have hard enough time myself to find close, affordable housing each year I’ve lived off-campus in Ann Arbor. Melody and I have talked about this on numerous occasions; I sometimes think students are more stressed out with housing negotiations than with classes during the “house signing time” of the year. Nevertheless, I hope to help Yongyi find a few places that might work out for him.

When I get back to campus in the fall I hope to take what I’ve learned from nanotube synthesis and apply it to biology. Since professor Liu’s lab is focused strictly on Physical chemistry, I don’t have a chance to pursue this type of research at the present moment, but feel nanotubes could have many implications in biological science such as with molecule detection and cancer research. In fact, one of Professor Liu’s former students named Hongjie Dai has conducted a lot of biological research with nanotubes at Stanford University. In one of this papers, I read, he attached the peptide RGD onto nanotubes and subjected these tubes through the bloodstream of mice to determine the efficiency with which these nanotubes contact localized tumors that express the alpha(v)beta3 cancer integrin. Though some of these nanotubes were found in the liver upon dissection, many of them localized to the site of the tumor; this is a promising result since it implicates the Kanzius RF (microwave) therapy as a potential treatment that might be available to cancer patients in the near future. Another one of Prof. Dai’s papers involves drugs bound to nanotubes through base-stacking, which could be equally promising. Therefore, one thing I have learned from my research experience so far is just how connected all the sciences are to one another, whether that is physical chemistry, biology, physics, or engineering. If I had came to this revelation earlier, I probably would have taken some of my former courses like physics of physical chemistry more seriously, now I have a new found passion for these two areas of science.