This podcast was produced for the Kavli Prize by Scientific American Custom Media, a division separate from the journal’s board of editors.
How do you make a piece of glass repel water? How to protect metals from harsh chemicals? Scientists have puzzled over how to transform surfaces for centuries.
Jacob Sagiv took a giant step forward in this area of research by discovering a way to transform a solid surface with an ultrathin layer of molecules.
He shares the Cowley Prize in Nanoscience with Ralph Nuzzo, David Alara and George Whiteside for discovering and applying the approach, which is used in everything from batteries to car windshields to dental implants.
Scientific American Custom Media, in partnership with The Kavli Prize, spoke with Jacob to learn more about his contributions to this work.
Megan Hall: Yaakov Sagiv knew that he wanted to be a chemist since childhood.
Yaakov Sagiv: I played chemistry since I was 10 years old. But of course, when you say chemistry, what do you think? You think of test tubes, boiling something, pouring liquid from one beaker to another.
Hall: By the time he was in graduate school, Jacob had progressed from playing with test tubes to manipulating molecules.
bent: A chemist’s dream is to have a handle on each molecule, to be able to place it in the right place and build from molecules. This is the ultimate goal that every chemist would dream of.
Hall: So far, Jacob has tried different ways to arrange the molecules by dissolving them in a thin plastic film. He discovered that if he stretched this film, the molecules would line up and he could measure them.
bent: It’s in a solid, which is a polymer, and you can control how those molecules are organized by doing that, and it’s been useful.
Hall: But by the time Jacob finished his doctorate, he yearned to do more. And he needed a job.
bent: I was looking for a post graduate position somewhere. And I had a friend, a colleague, who also played with molecules and polymers. On his desk I suddenly saw a paper with some strange pictures.
Hall: These amazing drawings were simple – just lines and circles. But they were molecules arranged in a single layer.
bent: I had never seen anything like it, so I asked him what it was? And he said they were monolayers. I asked what it was and he began to explain it to me.
Hall: Jacob’s friend explained that these monolayers were formed by displacement of molecules in water. Not just any molecules – a certain type, one end of which is attracted to water, and the other is repelled from it.
bent: So if you put them on water, they will stick to the surface of the water. But they do not dissolve, do not go into water.
Hall: Think of these molecules as matchsticks, with a head that is attracted to water and a tail that is not.
He bent: When you throw them on the table, they scatter randomly. If you put them in a box and put them together and there is no room for them to move, then they are aligned.
Hall: This is mostly done by scientists. They lined up all these matchstick-like molecules by gently pressing on the surface of the water until they all stood up straight, but on their heads.
bent: Then it’s like a carpet floating on water and all the molecules are aligned.
Hall: Scientists could then strain these molecular carpets out of the water using glass slides. They then formed layers that could change the way the surfaces behaved.
bent: And they showed very good effects. For example, anti-reflective coating. You can reduce the surface reflection and so on.
Hall: This process was invented back in the late 1920s by Irving Langmuir and Catherine Blodgett.
Jacob had never read about their work before, but when he saw this article on his friend’s desk, he was immediately hooked.
bent: I remember I immediately knew that this was what I wanted to do. You know, it’s like falling in love.
Hall: He rushed to the library to learn more about the technique and went to the lab under Hans Kuhn, who was creating the technique developed by Langmuir and Blodgett.
bent: They started, I think, in the early 60s, playing with Langmuir-Blodgett. And that, I would say, was the Mecca of Langmuir-Blodgett at the time.
Hall: But there was a mystery that the laboratory could not solve.
bent: They asked themselves how we can align the molecules within the Langmuir-Blodgett limit.
Hall: The scientists in the lab thought that if they took a single layer of molecules and placed them on a surface covered with crystals, the molecules would fit into the pattern of those crystals. The problem was that the crystals they used dissolved in water.
bent: So to move the Langmuir-Blodgett, we have to submerge it in water. The moment we submerge it in water, the organization is lost.
Hall: To solve this problem, Jacob returned to his graduate school experience organizing molecules using thin polymer films.
bent: I said, OK, I have a better idea. I know how to make polymers that don’t dissolve in water. And I know that the molecules are oriented inside the polymer.
Hall: Jacob thought that if you put a Langmuir-Blodgett layer on a polymer film, you could organize the molecules.
bent: And then I started playing with it.
bent: nothing. The Langmuir-Blodgett monolayer does not want to reorganize.
Hall: He tried to figure out why it didn’t work for him in graduate school.
bent: Then I began to think, for a moment, why do they not match? They don’t level because they are hard carpets.
Hall: Langmuir-Blodgett monolayers were created by bringing large numbers of molecules together, and now they are stuck.
bent: They are like a solid, the molecules cannot move.
Hall: But Jacob saw this limitation as an opportunity.
bent: The best are the experiments that don’t work as predicted because I think our minds are limited to a certain type of thinking and an experiment can teach you more than you might think beforehand.
Hall: If the Langmuir-Blodgett monolayers were too compressed to rearrange, what if you didn’t use them at all? If you put the right molecules in a solution, do they organize themselves? Yakub tried.
bent: I only use an organic solution, not water. I dissolved the molecules in an organic solution. I dipped the proper surface. And immediately I got what I wanted. The molecules aligned and it was beautiful.
Hall: Jacob has just discovered that physical pressure is not required to create these monolayers. You can simply use the natural interactions between the molecules and the surface.
bent: But you have to know what to put in there. I mean, that solution has to be right, under the right conditions and the right molecules, and when it’s right, you just go down and take it out.
Hall: These layers, formed by chemical reactions rather than physical pressure, would come to be called self-assembled monolayers. And they changed the way we approach manipulating molecules and coating surfaces. But no one in the laboratory was interested in Jacob’s discovery.
bent: This is one of the problems when starting something new. It is very difficult to get people to do something else.
Hall: Everyone else in the lab was comfortable using Langmuir-Blodgett monolayers and didn’t want to change course. So Jacob left and got a position at the Weizmann Institute of Science in Israel, where he published several articles about his discovery.
But still, no one noticed it.
bent: Was the first Langmuir-Blodgett International Film Conference in 1982. I write to them that I want to attend. And I get a panel presentation, not a lecture.
Hall: Even his former teacher, Hans Kuhn, criticized Jacob’s self-assembled monolayers. He said they were not as good as those made with the Langmuir-Blodgett technique. Jacob argued that this is often the case with new technologies.
bent: Take, for example, the first airplane. Compare it to a hot air balloon. That was the main principle, but it didn’t work. That doesn’t mean we stay with the balloon forever.
Hall: But most scientists were not convinced. Even scientists from the Jacob Institute. He failed to get a position at the Weizmann Institute and was forced to resign.
bent: And I went to the unemployment office in our city of Rehovot and registered as a chemistry teacher, unemployed.
Hall: But slowly, Jacob’s luck changed. The Weizmann Institute of Science allowed him to return as an assistant professor and reapply for the position.
Also in America, his fellow laureates Ralph Nuzza, David Alara and George Whitesides discovered his work. Nuzzo and Alara also studied self-assembled monolayers at Bell Labs.
bent: They invited me to visit them at Bell Labs. It was fantastic. And they told me what they were doing. And I told them what we were doing.
Hall: Bell labs scientists have cited Jacob in their research papers. In 1989, Jacob finally got the position. He is now widely known for his contributions to nanoscience and chemistry, but it took time.
Hall: Jacob says that the best science is always driven by pure curiosity. But this does not always lead to success.
bent: You will never receive a grant stating that the purpose of this work is to satisfy your curiosity. Do you always need to be told what it’s good for? But if you think it’s good in terms of immediate application every time, you’re not going to make too much progress in terms of basic science.
Hall: Jacob’s advice to other scientists? If you want a good career, don’t follow his path. If you want to make an important discovery, keep moving despite the obstacles.
Hall: Jacob Sagiv is a professor at the Weizmann Institute of Science in Rehovot, Israel.
This year he shared the Cowley Prize in Nanoscience with Ralph Nutza, David Alara and George Whitesides.
The Cowley Prize honors scientists for breakthroughs in astrophysics, nanoscience, and neuroscience—changing our understanding of the big, the small, and the complex.
The Cowley Prize is a partnership between the Norwegian Academy of Sciences and Letters, the Norwegian Ministry of Education and Research, and the American Cowley Foundation.
This work was produced by Scientific American Custom Media and was made possible by support from the Kavli Award.
[The above text is a transcript of this podcast.]