How to Make Nanoparticles?

Gold nanoparticles deposited on polymer nanofibers Image Credit:Aaike van Vugt

Andreas Schmidt-Ott, Pioneer of this technique, talks about the evolution of producing building blocks for nanotechnology from the gas phase.

How Did You Invent the Spark Ablation Technique?

When I started as a Ph.D. student in 1976, physicists became interested in the special properties that very small particles were supposed to have according to theory. This was the dawn of nanotechnology, which exploits these properties for useful materials or devices.

My supervisor asked me to make small particles, but he couldn’t tell me how to prepare them. Note that they were just called small particles or atomic clusters. The term ”nanoparticles” did not exist yet.

So he asked me to just try to produce nanoparticles in a noble gas somehow. At that time the only proven method was the method of exploding wires.

So the first experiment I tried was to explode wires and it worked out somehow. But the method was not practical, because it didn’t allow you to have a continuous and stable output.

The research was bringing modest results, but one day there was a bad contact in the machine and the wires were not properly connected.

So when I turned on the high voltage I saw repetitive sparks. Attached to the machine there was a detector of nanoparticles, which revealed their presence. I was surprised because they were not coming from exploding wires but from the sparks produced by mistake.

Immediately, I became curious about this result and made a small and experimental device to reproduce the same process. The machine was composed only of a small glass tube with two electrodes at a fixed distance. With it, I started performing experiments applying high voltage discharges as a nanoparticle source.

From the beginning of my tests, I realized that spark ablation has unique benefits which I couldn’t find in other techniques. For example, with exploding wires, we were restricted to few materials, and any method involving heating elements released contaminants from these. However, we wanted to produce very pure particles for basic studies.

As we were initially interested only in the basic properties of these particles, we did not publish the spark ablation method at that time, and it took a while until I realized the extreme flexibility of this method and its enormous potential for technological applications. It took 3 decades until nanotechnology had developed so far that commercial exploitation of spark ablation looked promising to me. The extremely flexible process should turn out to be very useful for the discovery of new catalysts and perhaps their industrial production.

Furthermore, applications are to be anticipated in the fields of sensor production, electronics, medical diagnosis and therapy and many more.

Thanks to the many years that passed between the first application to basic science and exploitation for technological applications and thanks to a great research team, mistakes were eliminated, and we further understood the spark process. This formed the basis for the development of a commercial nanoparticle generator to provide building blocks for nanotechnology.

Which Was the Connection Between Doing the Research and Starting the Company?

As a researcher, you have a lot of good ideas but with most of them, you can’t make any commercial product that has a chance on the market. And as a basic researcher, you don’t even think of doing that.

When in 2014 Aaike Van Vugt and I sat together, he was working on his Master thesis on spark ablation and we thought about commercializing this method for making nanoparticles.

Now nanotechnology was growing fast, and we knew we were still in need of time to refine the machine, make the output more reproducible and the nanoparticle generator easy to use.

A few years later, the company VSPARTICLE we founded, was already able to offer a robust and extremely versatile nanoparticle generator to the field of nanotechnology. Here, the third co-founder, Tobias Pfeiffer, was essential, whose Ph.D. thesis research had already concentrated on improvement of the generator. We are now witnessing a strong demand for the generator in the field of nanotechnology research. This demand for our nanosized building blocks covers many fields like catalysis research, chemical sensors, cancer therapy and diagnostics electronics and much more.

What Did You Want to Enable People to Do?

A the beginning the idea was quite general, nanotechnology was growing and needed to produce devices and applications.

So we had the feeling that we had to catch the time and be the first ones to enable generation of nanomaterials based on extremely small particles in an easy, safe and reproducible way.

Aaike (CEO of VSPARTICLE) worked on this project during his Master thesis, so he realized that this spark ablation device was a very useful source with incredible benefits: you can produce clean, controllable nanoparticles of any (semi)conductive material. As we are able to produce arbitrary mixtures of conducting materials, the number of materials the generator provides explodes from some 40 elements to more than trillions.

What Kind of Benefits Does this Technology Have from a Broader Perspective?

We can easily state that sustainability is a big challenge for nanotechnology. Because most methods of producing nanoparticles or nanostructures produce waste.

In contrast, the amount of material you use with spark ablation is the same you convert into nanoparticles: this is a zero-waste technique. For example, in nanotoxicological research, you can start with a small piece of radioactive gold (that is very expensive) and convert 100% of the material into nanoparticles.

Which Were the Main Challenges You Had to Face to Start the Company?

The first one was getting the right people and we have been very lucky.

Aaike has the necessary entrepreneurial motivation and talent, and we both knew Tobias Pfeiffer very well. He was the obvious CTO because he had dedicated his Ph.D. thesis to the spark, so he was the best possible expert to involve. I was afraid he might not want to take a risk, but he luckily agreed to join us in this adventure, and his expertise proved to be essential for the success VSPARTICLE has already had to date.

That was the nucleus, and the company has strongly grown since then. Tobias Coppejans, also my former Master student, who had meanwhile gathered valuable industrial experience, was the fourth partner to join, and Aaike had a lucky hand in recruiting further personnel.

What About Challenges at a Scientific Level? Did You Have to Convince Researchers that this Method Works?

When you come up with something new, you always need to convince people. The most difficult sector is catalysis because it is a very delicate process, where small changes of the catalyst surface have large consequences. This makes people stick to those solutions that have been proven to work, and the motivation to try a new direction is often small. It is the versatility and variability of our process that is convincing more and more colleagues from catalysis to give it a try, especially the option of easily mixing in arbitrary constituents.

What About the Future of Optimization of Catalysis?

Innovation and optimization in catalysis are possible only by introducing more flexible approaches. The generic aspect of the VSPARTICLE approach, with which in principle any catalyst can be produced, mixing anything with anything, is the key to optimizing and discovering new catalysts, and, on a long run, to drive industrial production.

What Has Changed During the 40 Years of Your Research Activity?

People are exposed to a higher degree of stress. In the “old days”, people were driven more by their curiosity or by the pleasure of engineering a new device. Increased competition has led to the creation of quantitative success indicators that are applied to judge the researchers’ performance. People are thus driven more by external demands, and these cause stress. Any effort coming from an inner motivation does not cause stress symptoms, even if the resulting effort is much larger. Staying in the lab overnight for the sake of obtaining a nice result was quite common when I did my Ph.D., but I had great pleasure from my work! In recent years we have gotten used to publications on unfinished work in order to get the publication, which counts for the score. Taking the risk of trying something new that might not work is considered dangerous because the publication is not guaranteed. The cause of this change is probably globalization. Every university and research institute competes with every other university and research institute in the world, so the managers want their indicators to be good. I am not able to name a safe recipe against this development. However, if a university would look more for qualitative criteria, e.g. the originality of research, that could mitigate the negative effect. The problem is that these judgments would be perceived as less objective. However, I believe that the absence of stress and new room for risk and creativity would then even drive the indicators higher on a long run. Discoveries need brave researchers willing to take a risk. Because doing research should mean also to do crazy things, like trying something new just to see what happens.

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