Partial Results From Summer

I haven’t posted my summary blog of this past summer until now because I have been communicating with my professor and other members of the research group, as I tried to make sure the results that I am about to publish are ready for public. I know when I posted my first blog, I talked about the topic of my research, which was Interfacial Characterization of Graphene/Polyamide Nanocomposites. It focused on understanding the interaction of graphene oxide (GO) and polyamide (PA) as materials for nanocomposites. I mentioned that the fundamental features of the interface could be very significant for future research on optimal selection of materials, as well as incorporation, for graphene/polymer nanocomposites.

I did manage to achieve some progresses on graphene/polyamide nanocomposites. But at this stage, I am not sure it’s a good idea to publish it because they are not yet conclusive. However, due to my role in the whole research group, I have been scanning a lot of different samples. And they are all materials that associate with the topic of nanocomposites.

For the GO that I scanned, I had to go through an analysis of the images. As I have talked about in my previous blog, we commonly use graphite and mica as substrates for our work because they are very flat. If the substrate is very rough, it could be hard to determine the height of the target. Targets could be distorted, or there may be too much ‘noises’ for analysis as I would be looking at the topography of the substrate instead of, in this case, GO. And as I described previously, a height image shows the topography of the sample I am looking at. Using a software, I can then take a cross section of a flake, indicated by the dotted line. The cross section – XZ plot – allows me to see the data of height along this line. So that I could interpret that if the sheets are single layer sheets or they are on top of each other, or they have never been exfoliated at all.

Graphene Oxide on HOPG

Graphene Oxide on HOPG

 

This is an example of one of the AFM height images that I took of GO sheets on graphite. Compared to mica, graphite tends to show steps on an atomic level after peeling. These unreduced GO sheets have the thickness of 1 to 2 nm, despite they could lie on a step of the substrate. The typical lateral size of unreduced GO sheets in this image is 0.5 by 0.5 µm. Nanocomposites prefer GO with decent size. I’ve introduced the incentive of incorporating polymers with GO, which was strengthening. Thus GO debris would not play effective role.

 

Studying varied GO has been essential before we proceeded to any further tests on the incorporation of nanocomposites and the characterization of interfacial features. I am glad that I have been able to work with some awesome people through the summer. It was not only a process of learning but also an experience of studying applied science. Thanks to Charles Center and the alumni that has generously offered me grant for the summer research. And thanks to all the members of my research group who has been teaching me a lot!