Everything started from carbon nanotubes – a material that is still immensely popular but 5 or 6 years ago it was an undisputed hit. The ways in which such tubes could be used intrigued Prof. Leon Gradoń, Ph.D., Eng., and Leszek Stobiński Ph.D. from the Faculty of Chemical and Process Engineering at the Warsaw University of Technology (in 2006 Dr. L. Stobiński  was awarded the title of Assistant Professor in Taiwan). “And then, after 2010, the age of graphene began”, says Dr. Stobiński, and Maciej Gierej, PhD., Eng., adds: “You can say that graphene is a carbon nanotube cut lengthwise and rolled out”.

Assistance and cooperation

The material, called the hope and future of technology, caught the attention of the rector, Prof. Jan Szmidt, Ph.D, Eng. During a discussion on graphene an idea emerged to establish a graphene laboratory. It was open on 24 September 2015 thanks to EU funding and cooperation with the authorities of the Faculty of Chemical and Process Engineering (Prof. Eugeniusz Molga, Ph.D., Eng., and Wojciech Orciuch Ph.D.) Dr. Leszek Stobiński became head of the laboratory. The main task of the laboratory consists in the production of standardised graphene flakes with repetitive and strictly determined properties as well as in the development of methods of their application, and research into the properties of nanomaterials containing graphene flakes. To speed up and streamline their work on graphene, last summer the Rector appointed the Platform of Graphene Applications with Maciej Gierej as its head.

“We have four extremely active faculties: that of Physics with Prof. Mariusz Zdrojek dealing with optoelectronic applications of graphene, of Materials Science and Engineering with Prof. Andrzej Olszyna, of Mechatronics dealing with new materials based on graphene where Prof. Małgorzata Jakubowska does research into possible applications of pastes and inks made with graphene, and – of course – the Faculty of Chemical and Process Engineering with Stobiński”, says  Gierej. “We also want to look for new and cheaper ways of producing graphene flakes in this laboratory”, says Dr. Gierej. 

What is graphene?

The methods of graphene production applied today are laborious, time-consuming and costly. That is why the material itself is so expensive. The repetitiveness of the production process is another challenge. Each minor change means that we will obtain graphene with different properties.

Let’s not forget that we are talking about the graphene that is produced at the Warsaw University of Technology, that is graphene flakes obtained from graphite powder. There is also large-area graphene, called epitaxial or CVD, but that is something that the Institute of Electronic Materials Technology deals with. “CVD graphene is measured in square meters and ours – in kilogrammes”, explains Dr. Stobiński.

Graphene flakes are a fragment of the structure of a graphite grain composed of several graphene layers (graphene is a single layer of graphite – there are fewer than 10 of them in a graphene flake). Therefore, graphene flakes are a pile of layers. The distance between graphene layers in a flake is about 0.34-0.37 nm. Usually, graphene is available in the form of powder or suspension. “The human eye cannot distinguish between graphene and graphite powder as the latter is just as black and soils your finger, therefore, to be able to distinguish between the two specialist tests are needed”, explains Dr. Stobiński.

In search of applications

We are still looking for graphene applications. It is a well-known fact that depending on its quantity added to another material we can change the electrical, mechanical, optical and magnetic properties of the new composite and this means the improvement of its functionality and quality. This is true both for organic and inorganic materials. When they are enriched with graphene, they are partly able to conduct electricity and gain improved mechanical strength.

Graphene may also be used in fuel cells, supercapacitors, photovoltaics or lithium batteries. In Europe, USA and Asia the graphene industry is developing dynamically and the number of graphene applications is significantly growing.

Nanomedicine and nanobiology are keen on using graphene flakes in their oxygenated form, that is graphene oxide, although the results of research conducted in these areas are inconclusive. “Some say that graphene flakes can be dangerous for living cells, others say the opposite and that it has anticancer and antibacterial properties”, says Dr. Gierej. “However, we do not know what graphene material was analysed, what its size was, how many layers it was composed of and how it was functionalised”.

Graphene can be used for the purposes of targeted therapy. This is because it is possible to add various active biological materials (like proteins, DNA) or medicines to a graphene flake. “This may be the key contributing factor of the new quality of hybrid materials but it is hard to tell what role it plays here”, Dr. Gierej adds.

Visiting the Graphene Laboratory

The Warsaw University of Technology is already involved in conducting joint research with the Medical University, Warsaw University of Life Sciences and the Military University of Technology However, their scientists hope that private companies will take interest in graphene applications.

It is the Graphene Laboratory that is supposed to facilitate that. Anyone can go there for advice or an interview and leave with a sample of graphene flakes.

The Graphene Laboratory operating at the Warsaw University of Technology is situated on the ground floor of the Faculty of Chemical and Process Engineering (about 100 m²). It houses a PLN 3,000,000 worth of specialist equipment. It contains an ultra-high vacuum furnace (to heat samples), ceramic filtering system (to purify graphene oxide), ultrasonic baths (to delaminate graphene clusters) and a number of hot plate magnetic stirrers. The laboratory is equipped with two element analysers, one determines the content of carbon, hydrogen, nitrogen, sulphur and oxygen (elementary analysis), whereas the other one detects the presence of many other elements from carbon to americium (x-ray fluorescence spectrophotometer).

“And this device coats various surfaces with thin graphene layers, including foil”, Dr. Stobiński says. “Have a look, please – graphene oxide is yellow-brown and it is only after its reduction that it turns black”.

The Graphene Laboratory at the Warsaw University of Technology has an analytical balance (for mass measurement precise to five decimal places), a set for thermogravimetry and differential scanning calorimetry as well as an inverted microscope with knobs.

It is in the other part of the laboratory that graphene oxide and its reduced form are produced. That part houses specialist equipment, among other things a 20-liter glass reactor with heating and cooling jackets for the production of graphene oxide, a three roll mill with three rolls mixing various materials, plasma producing system (for powder modification) and an air conditioner measuring the ageing rate of samples.

„Half a kilogramme of graphite powder will produce about half a kilogramme of graphene flakes”, says Dr. Stobiński. “This process, including purification, takes us from 1 to 3 weeks”.

There is a team of thee persons working at the Graphene Laboratory on a daily basis. Apart from Dr. Stobiński, the team includes Marta Mazurkiewicz-Pawlicka PhD., Eng., and Dr. Artur Małolepszy. The team is supported by Prof. Robert Daniewski who shares his knowledge and experience with them.

Speaking with one voice

The tasks that WUT scientists set for themselves are clear: they focus on the production of tailor-made graphene, customised to meet the needs of specific applications, and on the lowering of the cost of its production.

The standardisation of research procedures is an important thing as is obtaining support from various institutions, including the government. That is why the initiative Graphene in Poland was established. “We have to remind our politicians that this material exists”, says Dr. Gierej. “To be heard in the right places we have decided to speak with one voice”.

Agnieszka Kapela

Office for Promotion and Information