Edge modification of pristine graphene

Graphene?

The discovery of graphene was one that caught the public’s imagination. Graphene, is a form of carbon where the carbon atoms are bound to each other in such a way that they make a series of hexagons. These hexagons all lye in a plane such that the material (graphene) ends up being a flat sheet. What was interesting about this material, was that it had a lot of interesting properties, properties that in isolation would be useful, but together made it what many called a ‘super material’.

You can imagine this as a material that conducts electricity better than any wire or metal, is flexible like a rubber band and is also stronger than steel. Also, because it is only one sheet of atoms thick, it is pretty much transparent too.

If you want to find out more there are numerous articles on it and a quick search will result in more than you could read about it.

Personal research

In 2018 I assisted with some of the work of a larger collaborative effort to find a better route to modifying the edge of graphene sheets. It’s very hard (if at all currently possible) to modify the actual graphene sheet to have different chemical structures without disrupting the beneficial properties of graphene itself. This means that generally an attempt to make graphene more useful by chemically modifying it, will result in graphene losing the very properties that made you choose it as the base material in the first place. Say you wanted to put it in a golf club to make the club lighter and stronger. The very act of making the graphene flakes chemically compatible with the club material would reduce their strength, leaving the golf club no stronger than before you started.

This negative effect of chemically modifying the sheet is quite localised though. If you were able to modify only the edges of a graphene sheet, leaving the vast majority of the sheet untouched, the sheet would keep its ‘graphene’ properties and have the extra functionality that you wanted.

This was the aim of our research.

Publication

The work has now been published by the Journal of Materials Science and is titled “A versatile route to edge-specific modifications to pristine graphene by electrophilic aromatic substitution”. It is an open-access article, so the whole paper is there to read if it takes your interest.

One of the interesting things with graphene that many people who don’t do research in the area don’t know, is that graphene is quite badly defined.

Many pieces of scientific work will say that they are working with graphene, but this is the subject of quite some dispute. To me, graphene is colloquially define as outlined in the first paragraph.

The more layers you stack on top of each other, the more graphene loses its special properties. Generally, any ‘graphene’ that is more than 10 sheets of graphene thick is no longer graphene but instead micro-graphite, which is far less exciting.

You can oxidise graphene a little, which makes it easier to handle and perform reactions on. It’s agreed that this isn’t graphene. If you reduced this (reducing is simply the opposite of oxidising), you should get back graphene and many would say that you do, but many of the beneficial properties are not as good as true graphene. This form of ‘graphene’ is called reduced graphene oxide, (again not as exciting as pure graphene).

Our work focused on leaving the graphene as graphene and only changing the edges to yield true sheets of graphene with useful chemically modified edges. This could allow it to be used in a wide range of applications from materials to drug delivery and power storage. In truth, I could write a far longer post about this.

It was a very interesting piece of research and whilst I’m not the primary contact for the paper, if you have any questions let me know in the comments and I’ll be happy to get back to you.

Much like my journey from research to the private sector, I would encourage anyone to follow the path between their sector and research. It’s fascinating and useful to have cross-sector knowledge even if it is just out of interest. Starting is often the hardest part, but by getting this far, you’ve already done that. You know about graphene edge modification chemistry.

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