8 March 2021
Dr. Josef Zwanziger
Canada Research Chair in Nuclear Magnetic Resonance Studies of Materials
Professor, Department of Chemistry, Dalhousie University
Dr. Zwanziger’s laboratory is developing new glassy materials for application in optical instruments and construction. They use a combination of experimental, computational, and theoretical approaches to understand the material’s performance at the atomic level.
The optical glass used in high tech equipment, including large image projectors and microscopes, contains about 50% lead. Lead makes the glass transparent, strong and resistant to temperature change, but it is a serious environmental hazard. Dr. Zwanziger’s team used predictive modelling – run on Compute Canada infrastructure – to develop lead-free alternatives.
What is your research exploring?
I work in the area of materials science. In short, we’re designing zero stress optical glasses without the use of lead or other environmentally harmful additives. Simply gluing or clamping a glass lens of a polarized light microscope (commonly used in geology, mineralogy and chemistry) will create enough stress to degrade the quality of the image. It’s been known for about 100 years that if you make glass with a really high lead content that this degrading effect doesn’t happen. Glass with a high lead content works well and is easy to make.
If it works so well, why replace it?
Because it’s harmful to the environment and the European Union has banned the use of lead in electronic equipment. The push is on to phase out the use of lead and our lab was approached by a company to see if it’s possible to make products that contain no lead.
What was the result of your research?
We solved it. We were able to figure out that there are other elements on the periodic table that are allowed environmentally and have the same type of interaction, for instance tin. We then developed a recipe to make tin glasses and many others that have the same properties as the lead glasses, but are safe to use. This is still fundamental research but we’ve proven it works. Corning has also tested it and shown it works. There’s another group in Japan that has put our ideas into practice. I’m absolutely certain that this will be used industrially – there’s no question about it.
Why is Compute Canada infrastructure important to your research?
The alternative was to actually make all possibly relevant glasses in the lab, which I would never ask a grad student to do. You’re dealing with really toxic stuff like mercury and thallium. Instead, we used Compute Canada machines to calculate all the different compounds in the periodic table, identify trends across different chemicals, and from that predict which materials mimicked the properties of lead. This computing power was critical to solving this problem. I don’t see how we could have solved it any other way.
Which Compute Canada regional networks to you currently use?
WestGrid and ACEnet. What I really like about Compute Canada is that it makes all the regional networks wide open so you can use any machine nationwide, regardless what region you happen to be in.
Is your research in this field continuing?
Yes. We have now begun to crack of the problem of how glass responds depending on the optical colour of the light used. Ideally, you want the glass to respond exactly the same no matter what type of colour you’re putting on it. We’ve figured out how to address that problem and make glass that doesn’t have any colour dependence. This research requires really big calculations which wouldn’t be possible without Compute Canada resources.