Q/A: Jill Millstone on the Future of Nanoscale Materials

Professor Jill Millstone is an Associate Professor of Chemistry at the University of Pittsburgh and an Associate Editor of ACS Nano. She currently works on metal-ligand chemistry. Her lab focuses on developing new tools and insights for nanoparticle synthesis to transform these particles into society-shaping technologies. She will deliver The Kavli Foundation Emerging Leader in Chemistry Lecture on August 20, 2018, during the 256th ACS National Meeting & Exposition. Her lecture will discuss how the interactions between metal atoms and ligands predict the final architectures and physical properties of nanomaterials, including dramatic changes in both optoelectronic and magnetic behaviors.

Learn More About Jill Millstone’s Career and Her Research:

Your concentration is in metal ligand chemistry with nanoparticle synthesis and performance. How would you explain that to someone who isn’t from that field?

We’re interested in the chemical mechanisms that govern the formation of nanoscale matter. What’s really interesting about the chemistry of making nanoscale materials is that it draws very heavily from both molecular chemistry–you know, traditional inorganic and organic synthesis, but it also draws from what we know about material synthesis in the bulk–so concepts like crystal growth and colloid and surface chemistry, typically more associated with industrial applications and bulk scale materials. What we learn is that combining theories from the two length scales creates a new world in chemistry, where we’re thinking about synthesis in ways that give us new opportunities to test the theories that we have and to invent new ones where they are useful. These types of conceptual leaps give us the opportunity to make new materials at this length scale, and across length scales. Whenever you have a shift in your perspective, it doesn’t just give you a new vision; it changes how you see what you’ve already been doing.

When I talk to other chemists about why these types of studies are important, I think about it in those fundamental terms: We’re thinking about new chemical principles of how to build matter. And what’s exciting about nanomaterials is when you construct that matter, and you understand its dimensions and morphologies, you often see properties that we don’t see from the same chemicals in either their molecular or bulk counterparts. So you get this treasure trove of new properties we can use in applications we care about. But it’s the fundamental chemistry that developed those materials that, to me, is the critical step and–of course, my animating life force. The idea is that you’re thinking about how chemistry can inform synthesis in a new area. Because chemistry is about making matter.

Would you say the resulting application is more important or the science behind the application?

You have to think about it in terms of ‘more important to whom’ and ‘more important for what.’ I think human beings want to contribute to the welfare of other human beings. I actually think that’s innate and in our nature. A controversial point, I’m sure. But I think we inherently want to help one another. And I think most scientists are also animated by a curiosity of the world around them.

I think what’s exciting about science is that when your internal drive is curiosity about the world around you, often times the more we understand about the world, the more we can do technologically. So I don’t see these as opposing concepts. I see them as complementary. I think that if someone is animated by what a material or chemical principle can do, then they’re going to contribute a lot in that area and we need that. But we also need people animated by “how does this work/why does this work,” because when we understand those principles, we can use them as a foundation to do many different things.

An analogy I use a lot is polymers. When you had Zeigler and Natta and early polymer chemists thinking about how to make polymeric materials and doing really beautiful chemistry, I’m pretty sure none of them envisioned that they’d be creating the building blocks that would then be used in everything from car bumpers to artificial hips. But it’s the chemical principles that they defined that got those materials off the ground and allowed us to have this incredible diversity of new tools and transformed many, many industries. So, I think you need both. I think you need the person that says, “wow I wonder if we could use this polymer for artificial hip joints,” but you also need the person who wanted to figure out how the polymer formed in the first place and had no idea about and no interest in hip joints.

What led you into your field?

I did undergraduate research in the group of Rick McCullough at Carnegie Mellon University, and I was working in conducting polymers. And, actually, a lot of the scientists in that lab have gone on to be really famous scientists, so I was very lucky to have so many great mentors, especially in my undergrad. But I was definitely not one of those undergrads that were just getting everything right away, in the lab 24 hours. I didn’t really wake up as a scientist and understand and really fall in love with the discipline until I got to grad school. I decided to work in the Mirkin group at Northwestern which was primarily a nanomaterials group at that time, an inorganic chemistry-driven nanomaterials group. I didn’t really know much about nanomaterials. I knew I really liked Chad Mirkin’s talk to the first years, but that was it. I was pretty clueless and just lucky that I landed there. I hope there’s some clueless first year who feels better now.

But when I got in the lab, I was lucky to have excellent postdocs who just were phenomenal at helping me understand what grad school was all about, and thinking about scientific discovery, and thinking about how you read the literature and you become inspired. After the first six months of failing reaction after reaction after reaction, I wound up making this nanoparticle that turned out to be kind of interesting, and I can remember when I was at the TEM, the electron microscope, and seeing that. And I turned to my postdoc who was working with me (Sung Ho Park, at Sungkyunkwan University now) and I was like, “Is this good?” And he said, “This is really good.” That moment started my journey of learning about how powerful and interesting elements are when they’re transformed to the nanoscale. And it just captivated me, it really did.

That was paired with a singular experience I had in a class at Northwestern, that was taught by Sam Stupp. He said something I had never heard before: “The ages of history are named after the materials that defined them.” So you’ve got the iron age, the stone age..and so on. All of the sudden I was like, ‘oh my god’ and you know I started thinking about that and really thinking about what does it take for civilization to progress? And you realize that’s a key. Knowledge of these tools goes so far in giving humanity a springboard from which to apply their knowledge and ingenuity. Now obviously, humans are very good tool makers, but we have to have the basic products from which to make those tools. Those two things combined just lit a fire in me, and I got pretty obsessed with nanomaterials.

But then, you know, as I got towards the end of my Ph.D. career, I loved all the chemistry I was learning and thinking how nanomaterials form, but I got this feeling that I really wanted to understand the different ways you could use these materials. Of course at that time, and still, now, the biggest issue facing us is energy. Where we’re going to get energy from. I realized that I wanted to learn more about ways in which people were trying to address that issue, so I went to work at Berkeley in the labs of Jean Fréchet and Paul Alivisatos learning about different types of solar cells that use nanomaterials and polymers. And ultimately, although that combination of materials wasn’t going to be successful in solar energy conversion, it taught me a lot about how interfaces in materials were key aspects of their performance, probably the critical aspect to understand. And actually, interfaces are very hard to control from a synthetic perspective–exactly what an interface looks like from a molecular perspective. And it continues to be hard to analyze them. What characterization technique do we use to look at an organic molecule on an inorganic nanoparticle?

I realized that this was going to be something I wanted to study during my independent career. How do you control the formation of nanoscale surfaces? How do you look at them with molecular resolution? When we do that, and we learn how to make them and learn how to characterize them, what then do we learn about nanoscale synthesis and nanoscale properties that leads us to these ideas for new applications that can come from these materials. Applications we know that are dormant within these materials, but that we can’t define until we define the material itself.

Did you have any challenges or setbacks? How did you overcome them?

Well, yes. Definitely. First of all, it’s very important to say that I’ve been lucky my entire career. I’ve had excellent mentors. And so, everybody’s going to be challenged. Science is challenging. If you’re doing the right science, you don’t know the answer to the experimental questions you’re asking. So it’s challenging for everyone, and I think the people who make it are the people who are surrounded by a good support team, especially good mentors, and I’ve been very lucky. I’ve had some of the best mentors out there. But I certainly had challenges, little and big, from projects not working to details in one’s life that become challenging.

Certainly, the biggest challenge I’ve ever had, ever, is being a mom and that happened last year, and it’s a challenge I’m still working through. It’s an exciting challenge, but it’s very, very challenging. Which is great, it’s a great thing to have two joys in your life rather than just one. My first joy was science and being a research chemist, and now I have a new joy. Both of those things, both chemistry, and your children, require your full heart and your full dedication. It’s a challenge to figure that balance out. I think one of the things I’ve learned over the last year is that sustained commitment will always produce a good outcome, even though your instantaneous outcomes may be negative or positive. Sustained commitment and sustained effort give an overall trajectory that is positive. I think you learn that in grad school, experiments fail but then eventually you keep going, and they work. I actually think this is true in life.

One piece of advice that stands out to me is that you can learn something from everyone. Every person you meet has something they can teach you. And that’s been very, very true. No matter who I’m talking to, no matter where I am, talking to a student, a person I meet in the grocery line, one of my colleagues, I am always learning things. And I think when your ears are open and your eyes are open, you’d be surprised at how much wisdom is out there. I’ve benefited a lot from thinking about how I can learn something from everyone.

The other big thing that I thought of that stays with me is to be humble. And being humble doesn’t just mean not talking about all the awards you won, or whatever. That’s a superficial kind of humbleness. But humble in your thoughts. Meaning that you don’t assume you know everything about a research question, a research problem, a paper, a person; that you leave open the door that you could be wrong or that there’s something that you don’t know. I think that helps in being a good researcher and a thorough researcher, and I also think it helps in being a compassionate human citizen of the world.

I think the most exciting part of our research comes from the marriage between the analysis we do and the synthesis we do. What I mean is that each time we make a nanomaterial, and we look at the formation of the material—so we follow the synthesis using techniques like NMR to study the molecular conversions, as well as follow the products in the electron microscope. And we see this connection between the molecular chemistry and the solid state products. I think making those connections is probably the most exciting moments of our research. Because what I learn there, and what we find is these new pieces of chemistry that I was talking about in the beginning. We find, ‘okay this is how this concept of substitution in inorganic complexes actually applies to this concept of molecular absorption on surfaces that we learned in physics.’ And as we start to connect these two worlds, I think we gain two big things. First of all, we have these scientific insights that could now potentially lead us to a much lower barrier era of developing synthesis for nanoscale materials. But we also have the insight that’s necessary to scale up and ultimately use the materials in the applications we know they’re promising for, let alone discover the new properties they have which we can now associate definitively with the structure of the material. So I think when we make those connections between the molecular chemistry and the solid-state formation and structure, I think those are always the most exciting moments. We make those in a variety of different systems, with applications that range from bio imagining and light-driven catalysis, all the way to anti-corrosion applications and ship coatings.

What’s next for your research?

I think what’s next is, as we make these instantaneous connections—these connections within small areas of these syntheses, when we see this interplay between the molecular chemistry and the bulk material science, it’s always for a very specific system. And what we recognize now, and I think what we recognize as a community, is that often times these insights are not very general. And so one of the things that plague nanochemistry is that each individual reaction, each individual nanoparticle seems to be very isolated in the principles that govern both the formation and the properties of the architecture.

I think for us what’s next is trying to find general principles that can be applied for classes of nanoscale materials, and we’re doing that by, well: one can approach this in a variety of ways. You can try to do it computationally. And you can, of course, try to do this maybe using combinatorial chemistry techniques. But the problem is that in all of those cases, you’re not really sure what you’re screening for. I think if we can make some headway into what are hallmarks of general nanochemistry mechanisms, then we can start to use these fast technological tools that we already have (like robotic chemistry and computational prediction of structures and properties). I think in the phase of research that we are in now, we’re looking for the general principles that we can use as hallmarks and as markers for trying to develop these general nanochemistry principles.