Kyle Shepherd

Graphene Oxide Functionalization

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Project Overview

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During my PhD program with Dr. Rouzbeh Shahsavari, a senior PhD student named Sung Hoon Hwang was attempting layer-by-layer (LbL) assembly of materials. Working with Sung, the goal was to use the Graphene Oxide I had experience synthesizing as one of the layers for the LbL assembly. Our goal was to make a novel material using two separate 2D materials as the LbL building blocks, in contrast to most published research on LbL assembly that uses linear 1D polymers as the building blocks.

To achieve this assembly, we needed one material to be positively charged and the other material to be negatively charged so electrostatic forces would bind the two materials together into layers. Graphene oxide is naturally negatively charged due to the presence of functional groups such as -OH alcohols and -OOH carboxylic acids. Therefore, we needed to replace these functional groups with positively charged functional groups such as -NH2 amine groups to form our positively charged building block.

Unfortunately, all attempts to functionalize the graphene oxide were not successful. There are multiple claims of successful amine functionalization of graphene oxide in the literature, but based on further examination of the presented evidence, and based on our experimental evidence, these papers simply demonstrated reduced graphene oxide, and did not provide evidence of carbon to nitrogen bonds that would indicate successful covalent functionalization.

The current status of this investigation is that layer-by-layer assembly has not been performed. A LbL material could be created using graphene oxide as the negatively charged material and a polymer as the positively charged material, but this has been performed in the literature. It is uncertain what novelty our group could bring to this graphene oxide-positive polymer material.

A replication study of amine functionalization of graphene oxide could be performed if more rigorous synthesis protocols are followed and more rigorous characterization of the product is performed. However, support for this study has been minimal.

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Project Details

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A list of investigated synthesis routes is shown below.