Sunday, August 16, 2015

Challenges & Frustrations: Osuji Lab

When you pose a research question and conduct an experiment, you always want to find some sort of result that is in favor of your hypothesis. You’re not always going to find the results you want when you conduct your experiments due to a variety of reasons, however. Human error, substrate wear-and-tear, and chemical inconsistencies are just a few reasons.

The internship I experienced was founded on top of a single research topic, “Optimal Growth of ZnO Nanorods on Brass”. We were given a single procedure that was tailored for silicon substrates, a couple research papers, and the liberty of testing any variable we deemed fit for optimal array growth. With this liberty, however, came good and bad consequences. Valeria and I were able to learn from these consequences—nonetheless being disappointed by bad results. Changing the acetone percentage in the growth solution bore great results! We were able to determine that 15% acetone concentration was the best level for nanorod growth.

Changing the molecular weight of the PS-b-P4VP block copolymer didn’t produce the quality results we assumed would occur. Theoretically, the micelle cores are comprised on P4VP polymer chains. This means that the size of the P4VP cores is directly related to the nanorod diameter. This relation would mean that as the molecular weight of the P4VP increases, the diameter would increase as well. When we characterized our nanorods for each molecular weight state (235K/23, 41K/24K, 15K/7K), we saw no adequate growth pattern that was dependent on the molecular weight of the polymer. Another important frustration was the difference in uniformity between brass and silicon substrates. No matter how optimized we could make unseeded ZnO nanorod arrays on brass look, the arrays were never going to be as uniform as the silicon substrates.

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