Laura Rossi

You work in the field of soft matter. What does ‘soft matter’ mean exactly?

Soft matter deals with the study of soft materials, which are materials that can be easily deformed. These include polymers, emulsions, colloids, foams and certain biological materials. I mostly work with colloids, particles that are much larger than simple molecules. Because they are so large, the interactions between these particles are much weaker than they are between molecules and atoms, hence the term “soft”. Everyday examples of ‘soft matter’ are mayonnaise, butter, paint, blood and shaving cream. These products consist of large particles, or droplets, suspended in a fluid. We call these systems colloidal dispersions.

You say in your Eye-opener that you are making materials that you can control the properties of. What properties do you want to control?

For now we are focusing on mechanical properties. To do that, I design and develop particles (colloids) with a magnetic component. That way, I can use magnetic interactions to control the structure the particles will assemble in. The particles are designed in a way that if they approach each other with the right orientation they will attract. It is a bit similar to building with Lego bricks: due to the studs, you can only attach them in one direction. We do the same thing, but with magnets instead of studs.

In the laboratory we design the particles in such a way that they will self-assemble into the structure we want. That is pretty challenging.

What are you working on now?

My research is still very fundamental. I want to understand the interactions at play first, so I focus on two-dimensional structures for now. These are a lot simpler than the three-dimensional structures I eventually want to make. If you start with making complex structures and it doesn’t work, you have no idea of why it doesn’t work. There are too many factors that could influence the outcome.

The idea is that the way the particles are arranged determines the properties of that material. How deformable it is, for example, or how opaque. We can use this principle to make materials that adapt to the environment: that they can change from property a to property b when a magnetic field is applied, for example.

What would you use such a material for?

We are at a very fundamental stage now, but that doesn’t mean we are not thinking about possible applications. I think it is very important to keep that in mind from the very beginning. If we would scale up the process in the future, we will not be able to use very expensive chemicals or equipment. Therefore we try not to rely on those things at this stage as well.

One of the possible applications of this type of material is in biomedicine: you could use it to time drug release in the body very precisely. Or you could make very small robots that are activated by a magnetic field.

What do you want to achieve in the coming five years?

I want to take the first step into the programmability of these particles into simple structures. We could try to make a square lattice, for example. We would design the particles to form a square lattice and then see if they do. That would be an indication that we can also form more complex shapes eventually.