Making materials of the future

Polymer Technology at TU/e

 The Department of Mechanical Engineering at Eindhoven University of Technology focuses on research in three clearly defined areas: Computational and Experimental Mechanics (CEM), Systems, Dynamics & Control =  Dynamical Systems Design (DSD) and Energy and Flow = Thermo Fluids Engineering (TFE).

Its mission is to engage in long-term, generic, world-class research that matches the technological needs of the high tech industry, which is omnipresent in the Eindhoven region. The department acts as an incubator for leading research and also promotes close collaboration with industry. The scientific staff of the department (including more than 150 PhD students and post-docs) is active in several research groups that successfully combine fundamental and applied research to valorize ground-breaking science and ultimately help create products with a high societal impact.

This interview focuses on new work in rheology and rheometry: describing and measuring the flow of matter in a liquid or ‘soft solid’ state. One of the relevant technological applications is 3D printing, which is expected to replace many of today’s traditional - and inherently more wasteful - manufacturing techniques. Sustaining life on our planet in the long term is one of the greatest challenges we face today: the ability to use materials more economically and efficiently, and engineer their properties to exactly suit a specific application is part of the solution.

We talk to three researchers in the Polymer Technology Group of TU/e’s Department of Mechanical Engineering. They are Patrick Anderson, Professor in the structure and rheology of complex fluids and Chair of the Polymer Technology Group, Assistant Professor Ruth Cardinaels and PhD candidate Prakhyat Hejmady.

​​​​​​​Does TU/e have what it takes to lead in polymer research?

Patrick: TU/e has an excellent international reputation in Mechanical Engineering and is definitely recognized as one of the very best of the world’s universities in the field of polymer research. I am probably biased because I originally graduated in Applied Mathematics from TU/e. Even so, I feel confident in saying that we have a fantastic group of staff (from all over the world) here, a great deal of autonomy in what we do and the full support of the University Board. Although more than 75% of our work is bilaterally funded by industry, the focus is often very much on fundamental research that will probably not be applicable for several years. This is not a contradiction in terms: the businesses we work for and with are tackling some of the big, existential questions of the future. Perhaps that is the unique selling point of Eindhoven, and Dutch technology companies in general.

Ruth: I gained my academic qualifications at the University of Leuven in Belgium, with a further spell as a postdoctoral researcher at the Mechanical Engineering department of Princeton University, so I have significant experience in other universities. I came to Eindhoven in September 2014 because the work done here perfectly complements my areas of expertise. There were opportunities for my own line of research and I was offered a tenure track as Assistant Professor that very quickly led to a permanent position in 2017. I have absolutely no regrets. The very close links with industry were new for me, but highly beneficial because I have learned a huge amount about actual applications and the uses of materials. That broadens your perspective as a researcher.

Prakhyat: After completing my bachelor in Mechanical Engineering in India, I did my masters at universities in Belgium (Leuven) and Portugal before applying for a PhD position in Eindhoven in 2015. TU/e’s recognized position in the field and Patrick’s strong international reputation and leadership style swung the decision for me. Although the University of Leuven also has links with industry, Eindhoven is much more of a networking city. The combination of fascinating lab work, networking with companies and the lively social scene in Eindhoven really inspires me.

What exciting projects have you worked on during the past 12 months or so?

Patrick: Prakhyat’s PhD work involves an experimental Selective Laser Sintering (SLS) rig that will bring the quality of 3D printing to a much higher level. Unlike injection molding, no pressure is involved in 3D printing so the properties of the final material depend on the bonds formed in the liquid  matter stage. Rather than determining settings by trial and error, we will actually be able to ‘see’ exactly what is going on. This opens up a whole new line of research that will ultimately lead to printed products that have the same or better properties than products produced using traditional methods!

Ruth: Again, the 3D SLS printing project. This is a perfect example of what you can achieve through good collaboration and mixing in the right expertises. 3D printers have been available for a while, but they are just black boxes. Nobody knows what really happens during the process. We are  creating a printer where we can see how particles adhere to each other at microscopic level and develop a control rationale based on the materials themselves and a multitude of other factors such as the energy input. Another PhD candidate in our group is working on predictive models. The benefits for businesses are obvious: rational control over the process, high repeatability, no trial and error and no wastage.

Prakhyat: My project does indeed focus on one of the two 3D printing techniques – Selective Laser Sintering. This technique is much more complex than the alternative: Fusion Deposition Modelling (FDM). However the results with SLS are also infinitely better, hence our line of research.  Controlling a significant number of variables is the main challenge here. Our rig will allow us to describe how particles coalesce during SLS and establish a relationship between the sintering process conditions and the final material characteristics for different polymers. Very exciting stuff!

Extremely interesting work. Where will you be in three years’ time?

Patrick: The work on polymer printing will still be ongoing. We expect to have tangible results in around 10 years’ time. But the benefits will make that significant effort worthwhile: printed polymers will be just as strong and fit-for-purpose as injection-molded products, costs will be lower, stocks of materials can be reduced to a minimum and products can be made on demand rather than in batches. You could say that this work will revolutionize the world of polymers.

Ruth: I will be working on material customization in the area of SLS; i.e. economically producing materials with specific properties for specific applications, even in very small volumes, but also in other areas like food. For example, how do we produce foods with a different composition to satisfy the nutritional needs of different individuals? Easier said than done and we will have to combine all our expertise to achieve these outcomes!

Prakhyat: I expect to have catalogued several SLS polymer combinations. The experimental rig is the true breakthrough here, and one which has already proved many people wrong. Instead of using just one polymer to make a product, we will be able to combine different polymers at will. But, as you can perhaps imagine, the sheer volume of the associated experimental work is huge.

TU/e seems to be at the cutting edge of world-changing science. Would you agree?

Patrick: Our work speaks for itself and demonstrates that we are a leader in the field of fundamental polymer research. And that same inquisitive spirit and desire to change society for the better is present in every single department at the university. We set our staff the task of developing  meaningful products through targeted fundamental research, backed by government grants and funding provided by business partners. Eindhoven and TU/e provide the perfect setting for socially committed researchers and our policy is to recruit the best minds available for the job regardless of nationality, creed or culture.

Ruth: Eindhoven, with its network of businesses, and the mix of colleagues in my department have brought me to a different level as a researcher. There are so many opportunities for fundamental research here and the knowledge that your work will ultimately lead to a highimpact product is immensely exciting.

Prakhyat: I love Eindhoven and am involved in research that will help us all lead healthier lives. TU/e’s track record in this area is certain to attract many more projects of a fundamental nature and I look forward to being involved and furthering my career at the university, possibly as a part-time Professor.

What unresolved question or dream inspires you?

Patrick: My passion lies in mapping the transformation of molecules into a microstructure that undergoes a process to generate an engineered product with highly specific properties. The possible applications are practically infinite.

Ruth: I dream of tailor-made materials and foods that we can produce at will and in the quantities we require. 

Prakhyat: I dream of a healthier world where we use materials precisely and economically.