Deakin University Associate Professor Joselito Razal heads a group that looks at wet-spinning of nanomaterials and is unique in focussing on “how graphene fibres or at least graphene-based fibres can be produced in a scale that is relevant to industry”. He shares some insights with us on working at the frontier of nanomaterials, and of using graphene to produce novel fibres.
Every day in the lead up to the Internet of Industrial Materials Conference 2017 on August 17th we will be featuring conversations that Brent Balinski had with the presenters.
BB: Please tell us about your background
JR: I have now been at Deakin University in Waurn Ponds for two-and-a-half years, moving here from Wollongong University where I was based for eight years. Prior to that I was in the US and the Philippines. My research has always been about nanomaterials, and nanotechnology in particular. When I started on this journey I worked with various different nanomaterials, not engaging with graphene research until around 2010 when I was sharing an office at Wollongong with Professor Dan Li. At the time I was working on carbon nanotubes and conductive polymers, and making fibres from these materials for energy applications. It was when Dan Li made a breakthrough in his graphene research that we had the thought ‘Why not spin fibres from graphene?’
Following Dan Li’s work, we also made a breakthrough. Because when we first tried Dan Li’s graphene dispersions, unfortunately we were not able to make fibres from them. It was impossible to make strands or fibres or yarns of graphene using his material and using our already-established technique for spinning nanomaterials into fibres. So the breakthrough that I mentioned involved modifying the method in which graphene is made. So in contrast to Dan Li’s method, we were able to make graphenes that are significantly larger in terms of dimension; the sheet size is significantly larger than what the other method could produce. Which, long story short, enabled us to produce fibres from graphene.
I relocated here specifically to establish the wet-spinning technology. So over the years I learned many, many techniques and tricks in spinning different types of nanomaterials. Graphene is only one of them. Now there are many types of layered nanomaterials that have interesting properties.
Here at Deakin, what I’m doing is I have a research group that looks at many different types of nanomaterials. We still work on graphene. Why we chose to work on graphene is because that is the material that has shown great promise in terms of scalability. Probably not in the context of pure graphene fibres, but using graphene to reinforce other materials. These other materials could include polymer, for example. What we can do now is make insulating polymers, polymers that do not conduct electricity or are not able to conduct electricity. Now we can make them conductive. So you think of small amounts of graphene, again it goes back to large size of the sheets of graphene we were able to make. So with Imagine, what we are doing at the moment is we just started a three-month research contract. The aim is to identify whether the graphene that Imagine makes would be suitable for the fibre spinning application that we have established. Another aim is to look at whether the fibres can be produced at scale that would allow us to build prototypes in the form of a fabric. And for this project we have particularly looked at polymers that can extend or stretch, similar to what you see in compression garments. So these are stretchable materials. The idea is to be able to produce stretchable fibres that can at the same time conduct electricity. Whether this could be used for strain sensing or other types of sensing applications, we will evaluate that after we produce the prototype, but the main aim of the research, the short-term research, is to identify whether we can produce it and at the same time produce meaningful quantities to demonstrate prototypes.
BB: I’d like to ask about the importance of standards and repeatability relating to your research and to industrial adoption of graphene.
JR: Are you talking about the process of making graphene?
BB: As a material, being able to get a batch and to know exactly what’s in this.
JR: It is very important! I would go a little way back to give you an example on why carbon nanotubes don’t have many applications. When you synthesise carbon nanotubes you always get a mixture of metallic carbon nanotubes and some semiconducting types of nanotubes. This means that the properties you get from one batch to another is very different or could be different.
And I think that’s one of the reasons, apart from the difficulty in processing, that carbon nanotubes did not really take off in the market. So in terms of graphene, standardising the production, standardising the characteristics is very, very important.
And I think it’s very important in the context of scaling it up. Let me put it this way, in my research I work on scaling up processes.
Standardisation comes to how the actual material is characterised. So, for example, in graphene there are many types of graphene synthesis, you can produce it by CVD, by exfoliating from graphite, and characterising the type of graphene that you derive from a synthesis method may differ from graphene production companies or even from lab to lab. One would use, for example, Raman spectroscopy to identify defects in the sheet, and one would use XPS [X-ray photoelectron spectroscopy] for example. And even the interpretation of these data can be different!
BB: Lastly, is there anything you would like to add about why it’s an exciting time to be a researcher working with carbon nanomaterials?
JR: There’s so many reasons why it’s exciting, but I’ll speak for my field. So graphene fibres have been reported since 2012, I think, 2013, and what’s exciting about it is to look at the research literature from academics, you’ll see many papers that demonstrate new applications of graphene fibres. And this ranges from supercapacitors to batteries to sensors. And if you look at, say, ten papers, you can see that this paper has modified one part of a particular device, this paper has modified another part of a particular device, and so what academics have been doing at this stage is targeting the low-hanging fruit in graphene fibre research.
What is exciting about it is the low-hanging fruits in term of academic research are [picked]. In my opinion. So now it’s actually becoming very difficult to demonstrate that these applications can become a reality, and one of the big challenges in that area is that the fibres that have been demonstrated to produce prototypes, at least in the academic settings, have always been limited by the length of fibres that they can produce.
This is an edited version of an interview with Associate Professor Joselito Razal, ARC Future Fellow at Deakin University’s Institute for Frontier Materials. His presentation at the August 17 Internet of Industrial Materials Conference 2017 is titled “Why Conductive Fibres Are Important”. For more information on the conference, click here.