Liquid Crystal Science with Gray Medal recipient Dr Ingo Dierking

Meet the Department 7th June 2021

Dr Ingo Dierking from the Department of Physics and Astronomy of the University of Manchester was awarded the 2021 G.W. Gray Medal, the highest prize of the British Liquid Crystals Society (BLCS). The medal is awarded for outstanding contributions to research in the field of liquid crystal science and technology. It was first awarded 25 years ago, following the award of the Kyoto prize for Advanced Technology to George Gray (1926-2013), the discoverer of the first room temperature liquid crystal, which made Liquid Crystal Displays (LCD) a reality.

To celebrate this achievement, we spoke to Ingo about the importance and continued relevance of liquid crystal research.

What is a liquid crystal and how is it used?

Ingo: Everyone has heard of liquid crystals – everyone is familiar with the term, you’re looking at one now on your tablet, phone or laptop screen, but often, people don’t really know what it is! Liquid crystals are materials that have properties of liquids – they flow – and they also have anisotropic properties (difference in the size of physical properties depending on the direction that it is measured), for example leading to birefringence. The combination of birefringence, elastic behaviour and the response to applied electric fields are the basis for every liquid crystal display (LCD). Liquid crystal flow can be seen easily – press on your screen and you will see the colours changing – the elastic properties are responsible for your screen returning to normal. Liquid crystal’s force brings things back to the orientation they had before. Liquid crystals are the fourth state of matter (gases, liquids, solids and, liquid crystal!). They are located between the liquid and the crystal state, separated by phase transitions; just as melting ice or evaporating water.

Why did you start researching liquid crystal?

Ingo: This is a story that goes back through the years – I studied Physics at university, and physical chemistry was a way into a fascinating topic that I took on for the diploma thesis. This was pre-flat screen TVs (c.1989/1990). When I first saw liquid crystals under the polarising microscope I was instantly hooked! They are really beautiful when seen under the microscope – a large, aesthetic display of colours and structure – in materials this is called ‘textures’. From that point, I never really got away from liquid crystal research – we do very different work now, but it is still based on liquid crystals!

What are anisotropic liquids and liquid crystal composites and why are they important?

Anisotropic liquids are basically the same as liquid crystals. Our composite materials are liquid crystal based, with the addition of nanomaterials or polymers to influence their properties and tune them. Composites use the self-organised order of a liquid crystal and transfer that onto nanomaterials. On the one hand you can tune the properties for applications and on the other make ordered structures with the use of liquid crystals for nanotechnology – it even goes as far as the world of biomaterials.

What are the next stages of your research?

There are two general classes of liquid crystals – one is within displays, and involves the change into the liquid crystal phase in relation to alterations in temperature. The other class results from putting certain materials in a solvent, like soap molecules in water. These form liquid crystal phases as a function of concentration. Soap molecules, in a large concentration, become a liquid crystal – you can easily try this at home with washing powder. You also find this class of liquid crystals within biological materials, for example membranes. Membranes of cells are in principle liquid crystalline. There are plans to bridge the two types of liquid crystals; currently they are very much worked on separately by different groups. By bridging the knowledge gained from both liquid crystal classes, we can achieve a more universal and larger picture of liquid crystals going forward. As well as widening understanding about how liquid crystals fit in to the more general scheme of condensed matter systems – the more fundamental physics-based topics we currently work on are for example topological defects and solitons that are observed in many areas of physics. Like they are in liquid crystals as well.

So these are two of the larger problems relating to liquid crystals that will keep Ingo busy for the next years!

What is involved in your role as President of the International Liquid Crystal Society?

The ILCS is the umbrella organisation for all liquid crystal people. It is an international organisation that includes different regions of the world as well as the affiliated national societies (e.g. The British Liquid Crystal Society). The job effectively involves being the principle executive of the board and supervising the business of the ILCS, as well as representing the society to the outside world! There are approximately 800 members, with an overarching goal to encourage the advancement, discussion and dissemination of results from liquid crystal-related research. The Society is involved in conferences to present research, and in awarding research prizes. The President is elected for a four year term, with another four years allocated to the outgoing, previous President on the Board. The role of the President depends on what individuals see as their remit, in many ways! Normal duties include awarding prizes, running workshops and facilitating discussions. Liquid Crystals Today is an open access journal newsletter associated with the society, which contains lots of fascinating articles and news about research developments. One of the main tasks of the society is to actually bring young people into the research area, encourage study and continued interest in liquid crystals, and we award travel bursaries as incentives to get involved. Bringing people together to discuss ideas, overlapping interests, collaborative research and problem solving is a great aspect of this work! It is very much an academic organisation – we are looking out for the next generation of liquid crystal researchers – PhD students and upwards.

Ingo is heading the liquid crystal research activities at the Department of Physics and Astronomy, and is mainly working on the physics and properties of anisotropic liquids and liquid crystal composites. He was recently elected President of the International Liquid Crystal Society (ILCS) for the period of 2020-24 and is the former Chair of the BLCS. The Gray Medal will be bestowed at the June 2021 BLCS conference, which will be held online for obvious reasons.

anisotropic propertiesbiomaterialsbirefringencecompositescondensed matter systemselastic behaviourelectric fieldsfourth state of matterfundamental physicsLCDliquid crystalliquid crystal flownanomaterialsphase transitionspolarising microscopepolymerstexturestopological defects and solitons